School Science Lessons
35. Geology, earth sciences experiments,  minerals, properties of minerals, rocks
2012-02-05 SP
Please send comments to: J.Elfick@uq.edu.au
Some content below is based on A Field Guide in Colour to Minerals, Rocks and Precious Stones, Dr Jaroslav Bauer, Octopus Books Limited.
See: Chemistry experiments and minerals
See: Interesting websites, Part 9, Geology, earth sciences
Table of Contents
35.22.4.0 Clay
6.0.0 Equipment and solutions
35.0.0 Geology, earth sciences
35.1.0 Geology fieldwork
35.4.0 Major groups of rocks
35.2.0 Minerals
35.3.1.0 Minerals mined at the Broken Hill mines, Australia
35.3.0 Ores and ore bodies
35.1.0 Rocks, major groups of rocks, igneous, sedimentary, metamorphic
35.4.0 Rocks and minerals, properties
35.14.1 Silicates group, polysilicates, polysilicon
35.5.0 Soils
35.0.0 Geology, earth sciences
35.1.0 Geology fieldwork, you will need:
35.3.01 Assay value of precious metals
35.21.01 Batholith, Igneous intrusions, batholith, dyke, sill
35.21.8 Classify igneous rocks in hand specimens
36.3.01 Composition of the Earth's crust, abundance of elements
36.3.02 Composition of the Sun, abundance of elements
35.34.1 Dendrites, false fossils
35.33.2 Dimorphism, aragonite
35.1.1 Dip and strike, direction of a stream
35.21.01 Dyke, Igneous intrusions
29.3.0 Earth's magnetic field
35.1.3 Examine a mineral or a rock
35.29 Faults
35.27 Folds
35.35 Fossils, Find fossils
35.34 Fossils How fossils form
35.23.4.1 Fracking, Oil shale and fracking (hydraulic fracturing)
35.21.01 Igneous intrusions, batholith, dyke, sill
35.40.2 Isostasy models
35.28 Joints
35.31 Limestone, Tests for limestone
35.40.1 Mapping contours, geological structures, erosion
32.1.2 Piezoelectricity, Voltage produced by piezoelectricity
35.33.1 Pyroelectricity, ferroelectricity
35.30.1 Quicksand
5.33 Collect rocks, (Primary)
1.32 Different rocks, (Primary)
2.36 Examine rocks with a magnifier, (Primary)
35.30 Sand, Examine sand with a magnifying glass
35.32 Sediments, Sort sediments
35.21.01 Sill, Igneous intrusions
35.1.2 Visit an outcrop or quarry, lode
35.2.0 Minerals
Actinolite Ca2(Mg, Fe2+)5(Si8O22)(OH, F)2
Agate SiO2
Albite sodium feldspar, Na(AlSi3O8)
Alkaline feldspars
35.23.2.1 Amber, C12H20O, succinite
31.1.01 Amber and rubbing experiments
35.14.3 Amethyst, SiO2
35.20.53 Ammolite
Ammonium chloride, (in volcanoes), NH4Cl
Amosite amphibole, (Mg, Fe)7(OHSi4O11)2: 35.20.3 (See 2.2)
Amphibole common horneblende, NaCa2(Mg, Fe2+ Fe3+Al)5(Si,Al)8O22(OH,F)2
Anatase titanium (IV) oxide, titanium dioxide, TiO2
Andesine
35.20.1 Anglesite, lead sulfate, lead vitriol, PbSO4
Anhydrite, calcium sulfate anhydrous, "snake alabaster", CaSO4
Anorthite
35.20.2 Antimony, natural antimony, Sb
35.21.3.1 Apatite, Ca5[F(PO4)3]
Aragonite calcium carbonate, (pea stone in hot springs), Dimorphism, CacO3
Argentite, silver glance, Ag2S
Arsenic, natural arsenic, As
Arsenic trisulfide, As2S3, orpiment, yellow pigment
Arsenopyrite, mispickel, arsenical pyrites, FeAsS
Anorthite, calcium feldspar, CaAl2Si2O8
Arsenolite, As2O3
Arsenopyrite, FeAsS
35.20.3 Asbestos, hydrous magnesium silicate
35.20.3.01 Augite
35.20.4 Azurite, basic copper carbonate, blue carbonate of copper, 2CuCO3.Cu(OH)2
Barytes, barite, heavy spar, BaSO4
35.20.5 Bauxite, hydrated aluminium oxide, Al2O3.2H2O
35.22.4.4 Bentonite, Al2Mg(OH)2[Si4O10](Ca,Na)x.4H2O
Beryl, Be3Al2(SiO3)6
Biotite mica
Bismuth, natural bismuth, Bi, salts for medical use
Borax: 35.13.3.1
35.20.6 Bornite, bournonite, Cu5FeS4
Brookite, TiO2
35.3.3.1 Bustamite, calcium manganese silicate, MnCaSiO6
Cadmoselite is a  rare cadmium mineral containing cadmium (II) selenide, CdSe
Cadmium sulfide minerals, greenrockite and hawleyite minerals
35.19.0 Calcite, calc-spar, CaCO3
27.6.4.1 Calcite crystals (Physics)
35.20.10.1 Calomel, mercury (I) chloride, horn quicksilver, Hg2Cl2
35.23.1 Coal, coal tar
35.23.1.1 Coal seam gas, CSG, and coal to liquid, CTL, projects
35.19.2 Carbonates, CO32-
 35.22.7 Carving stones, Limestone, stone dust and carving stones
35.20.7 Cassiterite, tinstone, SnO2
Celsian, barium feldspar, BaAl2Si2O8
35.20.8 Cerussite, lead carbonate, ceruse, white lead ore, PbCO3
Chalcanthite, mineral, copper (II) sulfate
35.14.4 Chalcedony, SiO2
Chalcocite, copper glance, copper (I) sulfide, Cu2S
35.20.9 Chalcopyrite, copper pyrites, copper iron sulfide, CuFeS2
Chromite, FeCr2O4, iron chromium oxide, iron chromite, chrome iron ore, chromium ore
Chrysoberyl, alexandrite, Al2BeO4
Chrysoprase, SiO2
Chrysotile, Mg3Si2O5(OH)4
35.20.10 Cinnabar
35.23.1: Coal, coal tar
35.25.0: Coal seam gas, CSG, and coal to liquid, CTL, projects
35.20.11 Copper, Cu, natural copper
Coprolites, fossilized animal dung that may be mineralized but still give evidence of diet
Cornelian onyx, SiO2
35.20.12 Coronadite, lead manganese oxide, Pb2Mn8O16
35.20.12.1 Corundum, Al2O3 +, (ruby, sapphire)
Covelite, indigo copper, CuS
Crocidolite, riebeckite asbestos, tiger's eye, cat's eye, Na2Fe3Fe2[(OH, F)Si4O11]2
Crocoite, red lead ore, PbCrO4
35.20.13 Cryolite, sodium aluminium fluoride, Na3AlF6
 Cuprite, red oxides of copper, Cu2O
Diamond, C
35.19.1 Dolomite, CaMg(CO3)2
Emerald, Be3Al2(SiO3)6, natural emeralds always contain inclusions, but not if produced from seed crystal
35.20.13.1 Emery
Epsomite, hydrated Epsom salts, magnesium sulfate, bitter salt, (kieserite), MgSO4.7H2O, constipation medicine
35.15.0 Feldspars group
35.20.14 Fluorspars, -(AlSi3O8)
Fluorite, fluorspar, calcium fluoride, CaF2
35.22.4.5 Fuller's earth
35.20.15 Galena, lead (II) sulfide, lead sulfide, lead glance, blue lead, PbS
35.3.3.3 Garnet (spessartine) manganese aluminium silicate (Mn3Al2Si3O12)
35.20.17 Goethite, FeO(OH), hydrated iron oxide, hydrous iron oxide
35.20.18 Gold, natural gold, Au, for medical use
35.23.2 Graphite, diamond, C
Greenockite cadmium sulfide mineral, CdS
35.22.6 Gypsum, CaSO4.2H2O, calcium sulfate, plaster of Paris
35.20.19 Halite, rock salt, NaCl
Halloysite, Al4Si4(OH)8O10.4H2O, clay mineral
Hawleyite, cadmium sulfide mineral, CdS
35.20.20 Haematite, hematite, iron glance, specularite, Fe2O3
35.17.0 Hornblende (amphibole group)
Hyalite, silicon dioxide, glassy opal, SiO2.H2O, (nacre)
Hydroxylapatite, Ca5[OH(PO4)3]
Hydrozincite, zinc bloom, Zn[(OH)3CO3]
Illite, KAl4(Si, Al)8O20(OH)4, KAl4(Si,Al)8O18.2H2O, most common clay mineral
Iron, Fe, in ultrabasic rocks, meteorites
35.20.21 Ilmenite, titanoferrite, FeTiO3
35.17.0 Jadeite (in Hornblende)
35.14.0  Jasper, (in Quartz), SiO2
Kalinite
35.20.21.1 Kaolinite, kaolin-type clays, Al4[(OH)8Si4O10]
Kerargyrite, horn silver, AgCl
35.20.21.2 Kyanite, disthene, Al2(OSiO4)
Langbeinite,  K2Mg2(SO4)3, may be in in "potash" fertilizers
35.20.55 Lapis lazuli
35.20.22 Lead, Pb
7.2.2.23a Lead paint
7.2.2.23b Lead, Tetraethyl lead
Limonite FeO(OH), Fe2O3.xH2O
Magnesite, bitter spar, MgCO3
35.20.23 Magnetite, Fe3O4
See pdf: Magnetite nanoparticles, Ferrofluid
4.71 Natural magnets (magnetite)
35.20.24 Malachite, copper carbonate, Cu[(OH)2.CuCO
35.23.3 Marble, CaCO3
35.20.25 Marcasite, FeS2
Mascagnite, ammonium sulfate
35.20.3.1 Meerschaum
Melanterite, Iron (II) sulfate
35.20.26 Mercury, Hg
35.16.0 Mica group
27.5.3.7 Mica interference (Physics)
27.6.4.8 Colour with mica (Physics)
Microcline
35.20.27 Millerite, hair pyrites, NiS
Minerals mined at the Broken Hill mines
Minium, red oxide of lead, Pb3O4
Mirabilite, Glauber salt, Na2SO4.10H2O
35.20.28 Molybdenite, molybdic ochre, MoS2
Molybdite, molybdem ochre, MoO2
Monazite CePO4
35.22.4.3 Montmorillonite (smectite), (Al,Mg)[(OH2)Si4O10].(Na.Ca)x.4H2O
Moonstone (Feldspars), K[(Si,Al)4O8]
Muscovite mica
35.20.54 Nacre, mother of pearl
Nahcolite, thermokalite, sodium hydrogen carbonate mineral, NaHCO3, in evaporates
Natron, sodium carbonate decahydrate, Na2CO3.10H2O, (+ some NaHCO3 + NaCl), in saline lake beds
Nephrite
35.20.29 Nickel, Ni
35.20.30 Nickeline, niccolite, arsenical nickel, NiAs
35.21.5.1 Obsidian, volcanic glass
35.18.0 Olivine group, (Mg,Fe)2SiO4
Onyx, SiO2
35.14.2 Opals, SiO2.nH2O
35.14.2.1 Opal valuation
Orpiment, tinsel, deep yellow colour, ("gold-pimented")As2S3
Orthoclase feldspar, potassium feldspar, KALSi3O8
35.21.3 Pegmatite, beryl, topaz, tourmaline, zircon
Periclase, magnesium oxide, MgO
Perthite
35.23.4 Petroleum, crude oil
35.20.31 Platinum, natural platinum, Pt
35.20.32 Pyrite, FeS2, iron sulfide, iron disulfide, sulfuric pyrites, iron pyrites, fool's gold
Pyrolusite, MnO2
35.20.33 Pyromorphite group, lead phosphate, Pb5(PO4)3Cl
35.20.34 Pyrrhotite. iron sulfide, magnetic pyrites, FeS
35.14.0 Quartz, silica, (rock crystal, rose quartz, smoky quartz, milky quartz), SiO2
35.23.5 Quartzite, SiO2
Realgar, As4S4
35.20.35 Rhodochrosite, manganese carbonate, manganese spar, MnCO3
35.20.36 Rhodonite, manganese silicate, (Mn,Ca)SiO3
Rock crystal, SiO2
Rose quartz, SiO2
35.20.12.1 Ruby
35.20.37 Rutile, titanium (IV) oxide, TiO2
Sagenite, mineral, TiO2
Sanidine
35.20.12.1 sapphire
35.20.38 Scheelite, calcium tungstate, CaWO4
35.22.6 Selenite, satin spar, CaSO4.2H2O
35.21.6 Serpentine, antigorite, Mg6Si4O10(OH)8
Siderite, chalybite, spathose iron, FeCO3
35.14.1 Silicates group, polysilicates, polysilicon
35.20.39 Silver, natural silver, Ag
Sylvite, potassium chloride, KCl
35.23.6 Slate, (clay, mudstone, shales) C
35.20.40 Smithsonite, calamine, zinc spar, galmei, ZnCO3, (basic zinc carbonate, ZnCO3.2ZnO.3H2O)
35.20.41 Sphalerite, zinc sulfide, zinc blende, mock ore, mock lead, black jack, ZnS
Spinel, Al2MgO4
Spodumene, lithium aluminium silicate, forms 6 m crystals
35.20.42 Stibnite, antimonite, antimony glance, grey antimony, Sb2S3
35.20.43 Stilbite, lamellar zeolite, hydrated sodium calcium aluminium silicate, Ca(Al2Si7O18).6H2O
Strontianite, strontium carbonate, SrCO3
35.20.44 Sulfur, natural sulfur, S
Sunstone, (Feldspars), Ca(Al2Si3O3)Na(AlSi3O8)
35.23.7 Talc, Mg3Si4O10(OH)2
Tantanite, calcium titanium silicate, source of titanium, jewel stone
35.20.52 Tanzanite
Tellurium, natural tellurium, Te
Thorite, ThSiO4
35.20.45 Tin, Sn
Titanite, sphene, CaTi(OSIO4)
35.20.37 Titanium, rutile, titanium (IV) oxide, TiO2
35.21.3 Topaz, Al2(F2SiO4), Pegmatite, beryl, topaz, tourmaline, zircon
Tourmaline, (in Pegmatites), Na Fe3Al6[(OH)4(BO3)3Si6O18]
Trona, Prepare bath salts with sodium carbonate and with sodium sesquicarbonate: 12.1.28
Tschermignite, ammonium alum, NH4Al(SO4)2.12H2O
Turquoise, callaite, CuAl6[(OH)2PO4]4.4H2O
Ulexite: 35.13.3.1
35.20.46 Uraninite, pitch blende, pitch ore, UO2
35.20.47 Uranium, U
Valentinite, antimony bloom, Sb2O3
35.22.4.6 Vermiculite, Mg2FeAl[(OH)2AlSi2O10Mg((H2O)4]
Witherite, barium carbonate, BaCO3
35.20.48 Wolframite, (Fe,Mn)WO4
Wollastonite, calcium silicate, table spar, Ca3(Si3O9)
35.20.49 Zeolite, e.g. tetrapropylammonium (TPA) ZSM-5
35.20.50 Zinc, Zn
Zinc blende, ZnS
35.20.51 Zincite. red oxide of zinc, ZnO
Zircon, zirconium silicate, ZrSiO4
Zirconia, zircon-favas, ZrO2
35.1.0 Rocks
23.0 Rocks and soil (Primary)
35.24.0 Make artificial rocks
Major groups of rocks:
35.21.0 Igneous rocks
35.22.0 Sedimentary rocks
35.23.0 Metamorphic rocks
35.21.0 Igneous rocks
35.21.0 Igneous rocks
35.21.8 Classify igneous rocks in hand specimens
6.36 Cooling candle wax (Primary)
35.21.3.1 Apatite
35.21.1 Basalt
35.21.01 Igneous intrusions, batholith
35.21.2 Granite
35.21.3 Pegmatite, beryl, topaz, tourmaline, zircon
35.24 Make igneous rocks
12.16.6 Prepare an imitation volcano with baking soda
35.21.4 Pumice
35.21.5 Rhyolite
35.2.4.1 Scoria
35.21.6 Serpentine
35.21.7 Tuff
35.22.0 Sedimentary rocks
35.22.0 Sedimentary rocks
35.22.6.1 Alabaster
35.22.2 Breccia
35.22.7.1 Calcium carbonate dissolves in rain water
35.22.3 Chalk
6.43 Chalk (lime) content of the soil
35.22.4 Clay
35.22.5 Conglomerate (puddingstone)
35.22.6 Gypsum, (calcium sulfate) plaster of Paris
35.22.7 Limestone, stone dust and carving stones
35.39 Make clay pots (Primary)
4.33 Make sedimentary rocks (Primary)
35.25 Make sedimentary rocks
35.22.8 Mudstone, siltstone, marl, loess
35.22.1 Sandstone
35.22.9 Shale
3.67 Strength of plaster of Paris
35.23.0 Metamorphic rocks
35.23.0 Metamorphic rocks
35.23.01 Classify metamorphic rocks
35.23.2.1 Amber, C12H20O, Succinite
35.23.1 Coal
35.23.2 Graphite, diamond, C
35.26 Make metamorphic rocks
35.23.3 Marble, CaCO3
35.23.4 Petroleum, crude oil
35.23.5 Quartzite
35.23.6 Slate, C, clay, mudstone, shales
35.23.7 Talc, soapstone, talcstone, steatite, French chalk, Mg3Si4O10(OH)2, MgSi8O20(OH)4
4.32 Weathering rocks (Primary
35.24.0 Make artificial rocks
35.24.1 Make artificial igneous rocks, alum crystals, sulfur crystals
35.24.2 Make artificial rocks, sedimentary rocks
35.24.3 Make artificial rocks, metamorphic rocks
35.13.3.1 Borax
Borax has a sweet alkaline taste, hydrated sodium borate, di-sodium tetraborate (III)-10-water (borax), Na2B4O7.10H2O. Ulexite, alkaline taste, NaCaB5O6(OH)6.5H2O, hydrated sodium calcium borate hydroxide, is found associated wit borax often in evaporated lakes. When ulexite is polished and has two smooth sides it has the fibre optic property of projecting an image through internal reflection from the bottom of the to the top, so some people call it "TV stone"! The fibres have the formula B5O6(OH)6.
35.15.0 Feldspars group, "field stone", -(AlSi3O8)
Feldspars occur as alumino silicates of alkali metals and alkaline earths, have pink colour but red-green or yellow colour if impure and some are white, e.g. sodium feldspar or albite, hardness 6, white streak, glassy lustre, good cleavage in two directions, conchoidal fracture, relative density 2.35. It is the most common rock-forming silicate in igneous rocks and some sedimentary rocks. Feldspars are used in the interior of buildings as an ornamental veneer. Feldspars have dull surfaces unless light strikes at just the right angle. Feldspars in rocks may cause flashes of light because of reflection from two directions of cleavage at right angles to each other. Feldspars are used in glazes and the manufacture of glass, enamels, polishes, and roofing material.
Feldspars are divided into two groups:
Group 1. Alkaline feldspars, (K, Na)AlSi3O8, include orthoclase feldspar, microcline, and sanidine contain more potassium and less or no sodium, calcium may substitute for potassium and sodium, monoclinic or triclinic crystal system, crystals prismatic to tabular (also as irregular grains or cleavable masses), vitreous to silky lustre, colourless, white or pink (also green), white streak, Mohs hardness 6, two perfect cleavages at close to 90o, cleaves rather than fractures, not ferromagnetic, does not react with hydrochloric acid. Sanidine and orthoclase feldspar are the high temperature alkali-feldspar varieties, occur in alkali-rich igneous rocks such as rhyolite and granites. Microcline, the lower temperature alkali-feldspar variety, occurs in granites, pegmatite dikes and hydrothermal vein deposits. Orthoclase feldspar and microcline also occur in some metamorphic rocks and as discrete grains in immature sandstone. Minor colourless or white plagioclase intergrown with pink microcline is called perthite.
Group 2. Plagioclase feldspars, NaAlSi3O8, CaAl2Si2O8, include albite, anorthite, and andesine contain less or no potassium, triclinic crystal system, tabular crystals (also as irregular grains or cleavable masses), vitreous to silky lustre, white to grey colour (also blue to green), white streak, Mohs hardness 6, two perfect cleavages at close to 90o, cleaves rather than fractures, not ferromagnetic, does not react with hydrochloric acid, occurs mainly in mafic and intermediate igneous rocks, e.g. basalt, andesite. Note the pink colour and cleavage. Turn the specimen in the light and note flashing surfaces.
To distinguish the two groups, the alkali feldspars all have the perthite structure and plagioclase feldspars have lamellar twinning. Note the fine lines on a cleavage surface of plagioclase feldspar but not on orthoclase feldspar.
Feldspars include the following:
1. Potassium feldspar, orthoclase feldspar, KALSi3O8
Brown to colourless, vitreous pearly lustre, translucent to transparent, hardness 6-6.5, relative density 2.5, good cleavage, brittle uneven fracture, massive granular crystals, monoclinic system, main constituent of many different rocks
2. Sodium feldspar, albite, NaAlSi2O8
3. Calcium feldspar, anorthite, CaAl2Si2O8
4. Barium feldspar, celsian, BaAl2Si2O8
5. Moonstones, K(SiAl)4O8, feldspar, gemstone have blue-white spots that have a silvery colour like moonlight.
6. Sunstones, Ca(Al2Si3O3)Na(AlSi3O8), feldspar, gemstone
35.16.0 Mica group
The group has dark brown colour (biotite mica, Jean-Baptiste Biot 1774-1863) or is colourless (muscovite mica), hardness 2.5 to 3, white streak, pearly to glassy lustre, single perfect cleavage and relative density 2.8. It forms soft shiny flat flakes.
Muscovite mica or white mica, K2Al4Si6Al2O20(OH, F)4 contains no iron, so is clear and colourless.
Biotite mica, K2(Mg, Fe)6-4(Fe, Al, Ti)0-2(Si6-5Al2-3O20)(OH, F)4, is brown to black and is seen in granite as dark glittering specks. Mica can be split into very thin elastic sheets that can be split into thin transparent layers. On split faces the lustre is bright and pearly-white but other faces are dull and rough. Formerly it was used in place of glass in beehives and in foundries. Nowadays it is used as a heat resistant material in windows, stoves, eye shields, and sparkling makeup. Mica is a poor conductor of electricity so it is used in electrical appliances. Crush the specimen and note the sparkling surfaces.
35.17.0 Hornblende, NaCa2(Mg, Fe2+, Fe3+, Al5(Si, Al)8O22(OH, F)2
Hornblende has dark green to black colour, hardness 5 to 6, brown to grey streak, glassy to dull lustre, two imperfect cleavages, uneven fracture, and relative density 2.9 to 35.35. It forms small dark green to black crystals and is seen with biotite mica as dark patches in granite. Hornblende is in the amphibole group. Note the hexagonal cross-section of crystals, cleavage and colour of the hornblende specimen.
Actinolite is a similar mineral, Ca2(Mg,Fe2+)5(Si8O22)(OH,F)2, that includes nephrite or nephrite jade, the jade popular in China.
Nephrite jade, Ca2(Mg, Fe)5(Si8,O22)(OH,F)2 is a fine grained massive variety of actinolite that is used for ornaments and sculptures. The other jade is Jadeite, Na(Al,Fe)SiO6, NaAl(Si2O6),  pyroxene group, from Myanmar (Burma).
35.18.0 Olivine group (Mg Fe)2SiO4, peridote, chrysolite
The group has emerald-green to green-yellow colour, hardness 6.5 to 7.0, white streak, glassy lustre, poor cleavage, conchoidal fracture, and relative density 3.2 to 35.3. It weathers easily to leave the rock brown because of iron oxide stain. It occurs as sugary crystals that sparkle like quartz in basalt rocks. Quartz and olivine seldom occur together in igneous rock. Olivine occurs in the darkest rocks deficient in silicon. It forms gemstone crystals, e.g. chrysolite, which are transparent and have a glassy lustre. Volcanic "bombs" may have a lining of olivine crystals in the inner chamber. Note the colour, hardness and density of the specimen.
35.19.0 Calcite, CaCO3, calc-spar, Iceland spar
See 3.54.8: Prepare stalactite crystals
Calcite has white colour, in cracks in sedimentary limestone, hardness 3, white streak, glassy lustre, good cleavage in three directions not at right angles resulting in a characteristic rhombohedral shape, conchoidal fracture, relative density 2.7 and greasy to touch. Calcite occurs in four-sided crystals and as chalk and limestone. It forms from evaporation of sea water and occurs in sedimentary and metamorphic rocks, but not in igneous rocks. The crystallized varieties always break into little four-sided pieces when hit with a hammer. Iceland Spar is a clear crystal with refractive index 1.49 and 1.66 causing a double refraction effect, birefringence, double image caused by light polarization, used in the Nicol prism and in bomb-sights. Sea animals use calcite to build a shell or outer skeleton. Some types of calcite are used for building blocks, for making lime and in the glass and steel industries. Weathering of pyrite liberates sulfuric acid that may change calcite into gypsum and other sulfates.
In limestone caves, calcite occurs as stalactites hanging from the roofs of limestone caves and stalagmites that grow up from the floor.
Ca(HCO3)2 (aq) --> CaCO3 (s) + H2O (l) + CO2 (g)
Note effervescence with cold dilute hydrochloric acid, hardness and cleavage. Turn the specimen in the light and note flashing surfaces. If the specimen is a clear crystal, place it on a line and observe the refracted double line.
35.19.1 Dolomite, Ca(CO3)Mg(CO3), [MgCa(CO3)2] ( + some silica)
Dolomite has colour white to pink, hardness 3.5 to 4, glassy to pearly to dull lustre, white streak, good cleavage in three directions and relative density 2.8. Also, dolomite is a general term for rocks with a high ratio of magnesium to calcium carbonate. Note the colour hardness density lustre and slow reaction to dilute hydrochloric acid. Used as a sources of magnesium and in lining furnaces, fertilizers, ceramics, mineral wool, welding fluxes. Medical use to supplement calcium and magnesium deficiency.
35.19.2 Carbonates include the following:
1. Calcite, CaCO3
2. Dolomite, CaMg(CO3)2
3. Magnesite, MgCO3
4. Siderite FeCO3, chalybite, spathose iron
5. Smithsonite, ZnCO3, calamine
6. Witherite, BaCO3
7. Malachite CuCO3Cu(OH)2 (green colour)
8. Azurite, 2CuCO3.Cu(OH)2 (blue colour).
Calcite, dolomite and siderite are the main components of limestone.
35.20.1 Anglesite, lead sulfate, PbSO4
Anglesite has non-metallic lustre but is adamantine when crystalline and dull earthy, hardness 3, relative density: 6.2 to 6.4 and is colourless, white, grey, pale yellow, transparent green, transparent to translucent colourless. It may occur as groups of striated blocky rhombs and flattened simple to complex prisms. Anglesite, lead sulfate, PbSO4, is another widespread secondary mineral from the oxidized zones of the Broken Hill mine. It is found in vughs (irregular voids) and fractures in all mines in the outcrop area. The associated minerals are marshite, iodargyrite, pyromorphite, stalactitic goethite, and goethite matrix replaced by cerussite.
35.20.2 Antimony, Sb
Antimony occurs rarely as the metal. It occurs in hydrothermal veins combined with other elements, e.g. sulfur.
35.20.3 Asbestos
Asbestos is a group of fibrous silicate minerals that are compact and hard, sometimes resembling petrified root of a tree so was called mountain flax or salamander's wool. The word is derived from the Greek meaning incombustible. The colours range from brown to yellow to green. It usually occurs mixed with serpentine rock or mica schist. Tiger's Eye and Hawk's Eye, used for men's cufflinks, are altered varieties of asbestos with wavy bands of light that glow and ripple as you move them. Asbestos is a fireproof substance and formerly was widely used as a heat insulator, for packing and for fireproof garments and fabrics. Inhalation of the short asbestos fibres can cause the lung disorder asbestosis, mesothelioma lung cancer and bronchiogenic cancer. The manufacture and use of white chrysotile asbestos products were banned in Australia in 2003, and has been banned in many countries. Do not cut old "fibro" sheets or pieces of asbestos. Replace the whole sheets with non-asbestos sheets. The government may give advice on whether asbestos is present in buildings and how to get rid of it.
Asbestos is extremely toxic if inhaled into the lungs; strongly carcinogenic to the lungs; safe to touch but do not inhale the fibres. Causes asbestosis and the two cancers, bronchiogenic carcinoma and mesothelioma. Other forms of asbestos (amosite, anthophyllite, tremolite, actinolite and chrysotile) are not as dangerous by inhalation as crocidolite, but should be treated similarly. Specimens of ash should be stored in a sealed container until collection by a licensed waste contractor. Correctly embedded asbestos such as that found in geology teaching sample sets does not pose a threat to health provided that the embedding material remains intact. In Queensland, Australia, asbestos samples sealed in plastic bags were available in school minerals sets, but some boys broke open the plastic bags and handled the asbestos samples. So the Queensland government was forced to take out the asbestos samples from the school mineral sets.
1.0 Blue asbestos
1.1 Crocidolite, Na2Fe3Fe2[(OH, F)Si4O11]2, riebeckite, asbestos, tiger's eye, cat's eye, blue asbestos, amphibole, is the most lethal to humans. Crocidolite asbestos and blue asbestos is Not permitted in schools, store demonstration specimens in sealed containers or embedded in plastic.
2.0 Brown asbestos
2.1 Amosite, amphibole, (Mg, Fe)7(OHSi4O11)2
2.2 Mysorite
3.0 White asbestos
3.1 Actinolite, amphibole, Ca2(Mg, Fe2+)5(Si8O22)(OH, F)2, green-grey crystals, powdered mineral herbal remedy
3.2 Anthophyllite asbestos, amphibole, (Mg, Fe)7(OHSi4O11)2
3.3 Chrysotile, Mg3Si2O5(OH)4, the main asbestos mineral, white asbestos, a hydrous magnesium silicate, it is in the serpentine mineral group
3.4 Tremolite, amphibole, Ca2Mg5(OH, F)2(Si4O11)2
3.4 Byssolite, amphibole, Ca2Mg5(OH3F)2(Si4O11)2
35.20.3.01 Augite, (monoclinic, pyroxene, silicate), [(Ca, Mg, Fe2, Fe3, Ti, Al)2][( Si, Al)2O6]
Augite, Crystal systems, crystal habit, crystal form: 35.8 (See 4. Monoclinic)
Augite, Silicates group, polysilicates, polysilicon: 35.14.1 (See 3. Pyroxenes, MgSiO3, e.g. augite, jadeite, diopside)
35.20.3.1 Meerschaum, H4Mg2Si3O10
It is found as floating white lumps and was formerly used for tobacco pipes and holders. A soft light-coloured hydrated magnesium silicate found in Asian Minor. If newly dug up, it lathers like soap and has been used as soap.
35.20.4 Azurite, Cu3[OHCO3]2, copper carbonate
Azurite has non-metallic vitreous lustre, hardness 3.5 to 4, relative density: 3.77, intense medium to dark azure blue colour, transparent to translucent, colourless streak. Azurite (copper carbonate) has a habit consisting of short tabular prisms, equidimensional plates, long spear-like crystals with pyramidal terminations. The associated mineral is malachite, [Cu2[(OH)2CO3].
35.20.5 Bauxite
Residual sedimentary mineral that contains alumina and other oxides of aluminium in the amorphous or crystalline state. So it is more a rock-like mixture than a mineral. Usually formed by weathering in tropical regions. It is the most important ore for production of aluminium. Bauxite has non-metallic lustre, white streak, no good cleavage, can be scratched by the finger nail, white to brown-grey colour, uneven fracture, relative density 2.0 to 2.6.
See: Aluminium Oxide
35.20.6 Bornite, bournonite, Cu5FeS4
Bornite has purple to silver-grey to black colour, hardness 2.5 to 3, metallic lustre, black streak, poor cleavage, uneven to conchoidal fracture, and relative density 35.8. It resembles gold or iron pyrite but is more brittle than gold. Bornite is called "cog wheel ore" because twinned crystals form in that shape. Note the twinning habit colour and density of the specimen. Bornite may be a mixture of copper sulfides including Cu2S (chalcocite) and CuS (covelite).
35.20.7 Cassiterite, tinstone, SnO2
Cassiterite has white to grey to black colour, with fractured pieces having brown colour, hardness 1.5 to 2, white to grey streak, metallic lustre with the crystal faces often brilliantly shiny, cleavage poor, relative density 7.3. It is quite brittle. It usually occurs in ancient granite rocks, e.g. pegmatite, as small veins crossing the granite. It forms twin crystals. Note the density, colour and hardness of the specimen.
35.20.8 Cerussite, lead carbonate, PbCO3
Cerussite has a non-metallic and adamantine lustre, hardness 3 to 3.5, relative density: 6.55, is colourless or white or grey, transparent to subtranslucent, but may be opaque white to wine yellow to brown-yellow to smoky brown, colourless streak.
It occurs as ore grade concentrations as a secondary mineral from the oxidized zones at Broken Hill where most of it is opaque white. However wine yellow, yellow brown. smoky brown, transparent and translucent examples occur. It occurs as reticulated masses, complex arrowheads “twinned crystals”, and "jack straw" masses of tubular-shaped crystals. It is found in ore bodies and is one of the most abundant minerals of the oxidized zone. The associated minerals are malachite, [Cu2[(OH)2CO3], azurite, and bromian chlorargyrite.
35.20.9 Chalcopyrite, copper pyrites, copper iron sulfide, CuFeS2
Chalcopyrite has brassy yellow to green colour but often tarnishes bronze or iridescent to form “peacock ore”, hardness 3.5 to 4, dark green to black streak, metallic lustre, brittle, poor cleavage, conchoidal fracture and relative density 35.1 to 35.3. It is the main copper ore and is also a "fool's gold". Copper pyrite resembles gold or pyrite but it has a deeper brass colour and pyrite has hardness 6 to 6.35. Pyrite is more brittle than gold. It weathers to form the secondary minerals limonite, malachite and azurite. Note the crystal habit and softness of the specimen. Chalcopyrite, copper iron sulfide, occurs in veins in garnet, quartzite and garnet sandstone in ore bodies. The associated minerals are argentiferous galena and arsenopyrite FeAsS.
35.20.10 Cinnabar, HgS, quicksilver, mercuric sulfide
Cinnabar has brick-red to scarlet colour, hardness 2 to 2.5, red to scarlet streak, diamond-like lustre, but sometimes darker non-metallic lustre, uneven fracture, relative density 8.1. It is the most important mercury ore and is linked with volcanic activity, dangerous medicine.
35.20.10.1 Calomel, mercury (I) chloride, Hg2Cl2
Calomel, (mercurous chloride, horn quicksilver, horn mercury), is similar to cinnabar and may be found with it. Note the density, cleavage and colour of the specimen.
35.20.11 Copper, Cu, natural copper
Copper has copper colour that tarnishes to green, copper-red on a fresh surface but usually dark because of dark tarnish, metallic lustre, no cleavage, jagged fracture, copper-red shiny streak, hardness 2.5 to 3 and relative density 8.9. The rare native copper, Cu, occurs as rounded branches often with green or blue spots. Nowadays it occurs in mainly sulfide ores in veins or on the surface of crevices in sandstone, slates and igneous rocks. Pure copper is malleable, ductile and can be cut into slices. It has high thermal and electrical conductivity and resistance to corrosion so it is an excellent electrical conductor. Copper combines with zinc to form brass and combines with tin to form bronze. The name copper comes from the island of Cyprus.
Note the colour, crystal form and ductility of the native copper specimen. Copper, Cu, natural copper, has arborescent forms in large cavities, four-sided wire prisms, elongate octahedrons with repeated branches. Also, stalactitic or dendritic masses in wire-like groups and “nail head” crystals. The associated minerals are cuprite, Cu2O, red oxide of copper, and malachite, [Cu2[(OH)2CO3] in weathering zone of copper deposits.
35.20.12 Coronadite, Pb2Mn8O16
Coronadite, (lead manganese oxide, formerly called psilomelane), occurs as massive, stalactitic, shawls, cellular, botryoidal habit, sub-metallic glossy to earthy lustre, hardness 5 to 6, relative density: 3.7 to 35.7, colour black to brown black, streak brown black. Coronadite (lead manganese oxide) originally referred to as psilomelane, is massive, stalactitic, shawls, cellular, botryoidal habit. It is abundant in the upper levels of the oxidized zone and outcrop. The associated minerals are goethite that forms the matrix for a variety of secondary minerals..
35.20.12.1 Corundum, Al2O3 +, (ruby, sapphire)
Corundum as ruby contains Cr and is always red, sapphire contains Fe and Ti and is always blue-green, hardness 9. So a ruby is sometimes called a red .sapphire
See: Aluminium Oxide
35.20.13 Cryolite, sodium aluminium fluoride, Na3AlF6
Cryolite has colourless to white to yellow colour, and sometimes purple to black colour, hardness 2.5 to 3, white streak, greasy to glassy lustre, no cleavage, uneven fracture and relative density 2.935. The refractive index is 1.34 so the specimen almost disappears in water. It is a colourless rare mineral used as a flux in electrolytic production of aluminium from bauxite. Also, it is manufactured synthetically.
Note the disappearance in water, no salty taste and density of the specimen.
35.20.13.1 Emery
Emery is the naturally occurring mixture of the mineral corundum, magnetite and others. It is very hard and is used as an abrasive both as powder or as blocks or wheels.
35.20.14 Fluorspar, CaF2
Fluorspar, (fluorite, calcium fluoride, blue john, Derbyshire spar), has many colours, colourless if pure but usually purple or green or yellow, depending on dissolved impurities, hardness 4, white streak, glassy lustre, good cleavage in four directions, relative density 3.1. Coloured specimens may fluoresce in ultraviolet light or glow when heated. It occurs in veins in igneous rocks. Large crystals have been carved into small vases. It is used as a flux to smelt metals and to produce fluorine. The name comes from the Latin "fluo", meaning "to flow" because it melts at a low temperature. It can form twin crystals. Note colour, hardness, cleavage and possible fluorescence of the specimen.
35.20.15 Galena, PbS, lead glance
Galena, blue lead, silver grey to black colour, hardness 2.5, lead grey streak, metallic lustre, good cleavage in four directions, and relative density 7.35. It can mark paper. When hit with a hammer, galena breaks into perfectly cubic pieces because of its cubic cleavage. Tetraethyl lead [lead (IV) tetraethyl] was formerly used as an "anti-knock" agent in petrol (gasoline), but not now, because lead is toxic. Lead is used in X-ray shields, lead cell accumulators, ammunition, fishing sinkers, solder and type metal. Galena is the most important lead ore.
Note the density, and cleavage in the specimen. Galena (lead sulfide, PbS is the main lead ore mineral at Broken Hill. The silvery metallic lustre and cubic appearance characterize galena. It has a relative density of 7.35. Galena is also the source of much of the silver at Broken Hill, Australia. Silver atoms can substitute for lead atoms or be present within minerals such as acanthite (Ag2S) that have formed within the galena..
35.20.17 Goethite, FeO(OH)
Geothite, hydrous iron oxide, needle iron ore, acicular iron ore, has adamantine to dull lustre but silky in certain fine scaly or fibrous varieties, hardness: 5 to 35.5, relative density: 35.37, brown-yellow to dark brown colour, brown-yellow streak. Limonite, (brown iron ore, brown haematite, brown ironstone, is a cryptocrystalline mixture of mainly goethite, a weathering product of all iron deposits and in hydrothermal veins. It has a habit consisting of botryoidal, mamillary, stalactitic masses and crusts. It is abundant in the gossanous capping of the ore bodies. The associated mineral is coronadite.
35.20.18 Gold, Au
Gold has copper yellow colour like butter, hardness 2.5 to 3, gold to yellow streak, metallic lustre, no cleavage, jagged fracture, and relative density 19.3. Gold is malleable, ductile and can be cut into slices. Gold is a widely distributed metal and always occurs in a metallic state, generally as an alloy with silver, copper or iron. It occurs in thin irregular hydrothermal veins in a quartz reef, placer deposits and conglomerates. Gold does not tarnish so it has been used as the universal standard of exchange. Specks of gold can be separated by "panning" so that the greater weight of the gold causes it to settle, leaving the gravel at the surface. The "white gold" used in jewellery and decorating pottery is usually an alloy of gold and nickel, but used in dentistry it is an alloy of gold and platinum. Pure gold is rated at 24 carats, so 18 carat gold contains six parts of an alloy. Gold leaf, 23 to 24 carat, is gold beaten into very thin sheets for gilding decoration and electrical contacts, e.g. gold leaf electroscope.
Note the colour, and density of the specimen.
35.20.19 Halite, rock salt, NaCl
Halite has colourless or white colour, hardness 2, white streak, glassy lustre, good cleavage to break into cubes, conchoidal fracture, relative density 2.1. The cubic crystals may have an indentation in one surface. It forms from evaporation of sea water. It may rise from deep layers to form massive salt domes and act as an oil trap. Halite has a characteristic sharp taste. The inland salt trade was once important for many places, e.g. Salzburg. Table salt is always snowy white but natural salt has many different colours because of impurities. A red colour is caused by ferric oxide (iron oxide), grey is caused by clay, and brown is caused by plant matter. Used as table salt, road salt and glass manufacture. Note the cleavage at right angles and the taste of salt in the specimen. In the Bible, Matthew 5: 13, "Ye are the salt of the earth: but if the salt have lost his savour, wherewith shall it be salted? it is thenceforth good for nothing, but to be cast out, and to be trodden under foot of men." Although pure sodium chloride cannot lose its saltiness the rock salt used in biblical times often contained impurities. If the sodium chloride content was leached away or lost by evaporation in very hot countries the "salt” could indeed lose its salty taste. Also, fine grain salt may taste saltier than coarse grain salt due to the greater surface to volume ratio so that more salt dissolve in the saliva and reach the taste receptors on the tongue.
35.20.20 Haematite, hematite, Fe2O3
Haematite has grey to black and red to brown colour, hardness 5 to 6, red to brown streak, metallic to dull lustre, no cleavage, uneven fracture, relative density 35.3. It is weakly magnetic. The crystalline form is black and shiny. It is an important iron ore and is used in paints as a pigment and in jeweller's rouge polish. Note the red to brown streak and hardness of the specimen.
35.20.21 Ilmenite, FeTiO3
Ilmenite has black colour and gives a black powder as in "black sands", hardness 5 to 6, brown to black streak, metallic lustre, no cleavage, conchoidal to uneven fracture, relative density 35.5 to 35. It is slightly magnetic. The particles have been weathered from basic igneous rocks.
Note the density, lustre and streak of the specimen.
35.20.21.1 Kaolinite, Al2(OH)4(Si2O5), Al4Si4O10(OH)8
Kaolinite, commonly potassium alum, is a combination of potassium and aluminium sulfates, Al2(SO4)3.K2(SO4).24H2O, KAl(SO4)2.11H2O. It is a weathering product of feldspars, known as white clay, pipe clay, ball clay, Cornish clay and China clay, kaolin (also dickite and nacrite minerals) is used in the manufacture of fine porcelain that is almost pure kaolin. The cheaper grades are made with the addition of feldspar. It is a soft white powder, insoluble in water, dilute acids or alkalis. Kaolin clay contains mainly kaolinite and some illite. Kaolin is ingredient of anti diarrhoea medicines to absorb bacteria  and increase the bulk of faeces. It is very astringent and is used for purifying water. Soda alum or chrome alum are similar combinations where the potassium has been replaced by the corresponding metals.
35.20.21.2 Kyanite, Al2(OSiO4)
Kyanite, disthene, munkrudite, cyanite, rhaeticite (white-grey kyanite), (Greek: kyanos, blue), is an aluminosilicate mineral, hardness 4 -7, colourless streak, vitreous lustre. Found in aluminium-rich metamorphic pegmatites and sedimentary rock. Used in refractory and ceramic products, electrical insulators, abrasives, gemstones. Elongated, columnar crystals. Anisotropic, i.e. two different harnesses on perpendicular axes.]
35.20.22 Lead, Pb
Lead rarely occurs as the metal. It has a metallic lustre, a dark grey colour and high density of 11.34  g / cm3. Lead, Pb, occurs mainly as the lead ore galena (lead sulfide, PbS) It is characterized by a metallic silver lustre and cubic fracture. Cerussite (lead carbonate, PbCO3) and anglesite (lead sulfate, PbSO4) are found in areas where galena has been weathered or exposed to oxidizing groundwater. Typically this occurred at or near the surface. Lead was used in water pipes, roofing and pigments but is now mostly used in batteries for vehicles and other equipment.
35.20.23 Magnetite, Fe3O4
Magnetite (iron (II) diiron (III) oxide, magnetitum, ferrosoferric oxide, loadstone, triiron tetroxide, black magnetic iron oxide), has black colour, hardness 35.5 to 6.5, black streak, black powder, metallic to dull lustre, no cleavage, conchoidal fracture, cube-shaped crystals, relative density 35.1. It is called magnetic iron ore and has magnetic properties unlike any other mineral. Formerly, it was the strongest magnet known when known as lodestone from magnesia, Greece, but is no longer used as a magnet because much stronger and shaped magnets are needed. Fragments of magnetite will be attracted to a magnet or will affect a suspended magnetic needle. Magnetite has about 73% iron but it may also contain magnesium, chromium and titanium. Magnetite is widely distributed in igneous rocks and volcanic ashes so it is an important iron ore used in smelting. Note the magnetic property of the specimen and the streak. Magnetite is a folk medicine for liver function and a sedative. Magnetite is ferrimagnetic not ferromagnetic.
35.20.24 Malachite, copper (II) carbonate
Malachite, Cu2(OH)2CO3 or CuCO3.Cu(OH)2, has a non-metallic lustre, adamantine to vitreous in crystals that are often silky in fibrous varieties, dull lustre in earthy types, hardness: 3.5 to 4, relative density: 3.9 to 35.03, bright green and translucent or chalk green to lush green colour, pale green streak. Malachite, copper carbonate, [Cu2[(OH)2CO3], has botryoidal and sometimes velvety habit. It is found in ore bodies as powdery to compact fibrous crusts and hemispherical aggregates. The associated minerals are azurite and cerussite.
35.20.25 Marcasite, FeS2, spear pyrites
Marcasite has brass to yellow colour with a green tinge, hardness 6.5, green to black streak, metallic lustre, poor cleavage, uneven fracture, and relative density 35.8. So it is similar to pyrite but has radiating groups of twin crystals like a cock's comb. Old specimens may oxidize to give off sulfur in an exothermic reaction. Note the crystal habit of the specimen and compare the specimen with pyrite. An old specimen may have a sulfur smell.
35.20.26 Mercury, Hg
Mercury, is a bright silvery coloured liquid that forms spherical droplets if spilt. The relative density is 13.35. It was formerly called quicksilver and is the only metal that is liquid at room temperatures. It rarely occurs free in rock cavities. Mercury is used in thermometers, barometers, dental amalgams, silver-plating of mirrors and to separate gold from silver. Note the appearance and movement of mercury in a mercury thermometer. Do not allow students to touch mercury or to have any access to free surface metallic mercury.
35.20.27 Millerite, nickel sulfide, NiS, hair pyrites
Millerite has brass to yellow colour, hardness 3 to 3.5, green to black streak, metallic lustre, cleavage in 3 directions but not obvious in thin crystals, and relative density 35.3 to 35.35. It forms thin, needle-like crystals called "hair nickel" with a bright metallic lustre. It occurs in iron-nickel meteorites. Note the crystal habit, colour and lustre of the specimen.
35.20.28 Molybdenite, MoS2
Molybdenite has silvery grey to black metallic colour with a blue tinge, powder has the same colour as the crystal, hardness 1.5 to 2, blue to grey streak, can mark paper, good platy cleavage that forms flakes and relative density 35.7 to 35.8. Molybdenum, Mo, occurs as branches in pipes of quartz but is one of the less common metallic elements. The main use of this metal is in making blue pigment in glasses. Because molybdenite resists repeated shocks, it is added to steel to improve its strength and toughness. Note the greasy feel, the marks left on the fingers, and the blue streak of the specimen.
35.20.29 Nickel, Ni
Nickel is blue to white colour, hardness 35.5, grey metallic streak, metallic lustre, no cleavage, relative density 7.8 to 8.2. Native nickel is rare but it occurs in iron meteorites and in many different minerals, often oxidized to form green nickel "blooms", hydrated nickel salts. Nickel is weakly magnetic and malleable. Note weak attraction to magnets and density of the specimen.
35.20.30 Nickeline, niccolite, NiAs, arsenical nickel
Nickeline has copper-red colour with a red tinge, hardness 5 to 35.5, brown to black streak, metallic lustre, uneven fracture, and relative density 7.8. It occurs in masses. The name "nickel" comes from "Old Nick" (the devil) meaning it was worthless as a copper ore despite its similar colour. Nickel is used for kitchen vessels, nickel electroplating and tougher nickel steel for armour plating and machinery parts. An alloy of copper, zinc and nickel is called "German silver". An applied magnetic field causes nickel to decrease in length so nickel wire may be used in some types of computers. Note the colour, density, streak and sometimes an odour when heated.
35.20.31 Platinum, Pt
Platinum has steel-grey colour of native platinum but silver-white colour of pure metal, hardness 4 to 35.5, steel-grey streak, metallic lustre, no cleavage, jagged fracture and relative density 14 to 19 for native platinum and 21.5 for pure platinum. It does not react with air, water or strong acids (except a mixture of hydrochloric acid and nitric acid). It was called platina in Spanish because it was a white metal resembling silver. Native platinum is very rare and occurs in alluvial deposits as scales and grains or cubic crystals. Platinum is malleable, ductile and can be cut into slices. It is harder than gold and silver so it is mixed with those metals when making rings and other jewellery. Platinum vessels can hold acids because they do not react with them. Platinum is also used in scientific apparatus, electrodes and resistance thermometry. It has weak magnetism. Platinum black is used as a catalyst in chemical reactions. Platinum can absorb hydrogen and is used in catalytic converters to treat exhaust gases of motor vehicles. Note the density, colour and hardness of the specimen.
35.20.32 Pyrite, iron pyrite, iron sulfide, FeS2
 Iron sulfide, FeS2, iron disulfide, sulfuric pyrites, pyrite, iron pyrites, fool's gold, marcasite
Pyrite has pale brass-yellow colour, hardness 6 to 6.5, black-green to black-brown streak, but green or brown to black powder, metallic lustre, poor cleavage, conchoidal to uneven fracture, and relative density 35.02. It is the most common sulfide mineral and occurs as cubic crystals. It is found in lining cavities in faults and fractures in ore bodies. The associated minerals are calcite and rhodocrosite. It gives out sparks when struck with steel because of the fragments of sulfur igniting. Pyrite was used in the old wheel lock firearms to produce the spark to explode the gunpowder. Pyrite frequently shows traces of gold, silver, copper, nickel and arsenic. It can occur in mineral veins where it was commonly mistaken for gold, "fool's gold", but it may be rich in gold or copper or sulfur. It is used to manufacture sulfuric acid but is not smelted for iron production. Pyrite may be polished and used in jewellery, but it is not malleable. Pyrite may exhibits characteristic striations on the surfaces of the crystal faces. Note the hardness, streak and lustre of the specimen. Pyrite, iron sulfide, is found in lining cavities in faults and fractures in ore bodies. The associated minerals are calcite and rhodocrosite. Pyrite is not magnetic but is attracted to a magnet. Pyrite can be used in solar cells instead of silica. Pyrite crystals were used as crystal detectors in "crystal set" radio receivers.
35.20.33 Pyromorphite, Pb5Cl(PO4)3
Pyromorphite has non-metallic and resinous to adamantine lustre, hardness: 3.5 to 4, and colour consisting of shades of green, yellow, brown, grey and occasionally yellow-orange, sub transparent to translucent, relative density 7.04, colourless streak. Pyromorphite is the most common lead phosphate. It is a secondary mineral from the oxidized zone. It has a large range of habits and colours including coatings and sprays, simple hexagonal prisms, stout hexagonal prisms, branching aggregates, mamillated, botryoidal and colloform masses. It is found all along the lode outcrop. The associated minerals are coronadite, cerussite, secondary galena, and anglesite.
35.20.34 Pyrrhotite, FeS
Pyrrhotite, iron sulfide, has metallic lustre, hardness 4, relative density: 35.58 to 35.65, brownish bronze colour, black streak. It is found in veins, zones and bands in ore bodies. It can be weakly magnetic but not at Broken Hill. The associated minerals are calcite, galena, and chalcopyrite.
35.20.35 Rhodochrosite, manganese carbonate, MnCO3
Rhodochrosite, manganese carbonate, MnCO3 is a pink mineral found in fault zones along with other carbonate minerals, e.g. calcite.
35.20.36 Rhodonite, manganese silicate ([Mn,Ca]SiO3)
Rhodonite, manganese silicate ([Mn, Ca]SiO3) is the most abundant manganese mineral found in the galena-rich ore bodies. It has a range of beautiful red-pink colours.
35.20.37 Rutile, TiO2
Rutile, (titanium (IV) oxide, titanium dioxide, titania), has black or yellow to red to orange colour, hardness 6 to 6.5, brown streak, diamond-like lustre, good cleavage in two directions, conchoidal to uneven fracture, relative density 35.2. Titanium is used in the aerospace industry to produce low density corrosion-resistant steels. Titanium dioxide has replaced lead in lead paint. Titanium forms a protective layer in air, a passive oxide coating. Note the lustre, hardness and streak of the specimen.
35.20.38 Scheelite crystals, calcium tungstate, CaWO4
Scheelite has white to orange to grey colour, hardness 35.5 to 5, white streak, diamond-like to greasy lustre, poor cleavage, conchoidal to even fracture, and relative density 6. The crystals are usually not water-worn, so they keep their characteristic pyramid shape. They are transparent to translucent and may be bright or dull, with rough surfaces. It fluoresces blue in ultraviolet light. This mineral occurs in veins in granite rocks with cassiterite or fluorspar. Scheelite is an important ore of tungsten, W, used to increase the hardness of steel.
Note the crystal habit, fluorescence, and lustre of the specimen.
35.20.39 Silver, Ag
Silver has silver white shiny colour that tarnishes to a black colour, hardness 2.5 to 3, silver to white streak, metallic lustre, no cleavage, jagged fracture, and relative density 10.5 if pure but 10 to 12 if impure. It is malleable and ductile, can be cut into slices, and is one of the best conductors of electricity. It is a precious metal ranked next to gold and was once obtained from natural large masses but now is a by-product from the refining of lead, zinc, copper and gold. Silver can be moulded and shaped to form jewellery because of its pure white colour, softness and toughness. Note the colour and tarnish of the specimen. Silver has massive, wire habit The associated minerals are gold and copper. Silver, Ag, occurs in a variety of minerals but most of the silver is found as trace amounts of silver mineral locked up inside the lead mineral, galena. Sometimes silver occurs as big lumps, nuggets, of the metal itself. Only silver ever comes out of the ground as a metal. Lead and zinc are always locked away minerals, as is most of the silver. Silver is largely used in the photographic industry although it has uses in jewellery, electronics and silverware. Silver has massive, wire habit The associated minerals are gold and copper. Silver occurs in a variety of minerals but most of the silver is found as trace amounts of silver mineral locked up inside the lead mineral, galena.
35.20.40 Smithsonite, ZnCO3
Smithsonite, native zinc carbonate, and calamine (basic zinc carbonate, ZnCO3.2ZnO.3H2O) have a non-metallic and vitreous to waxy lustre, hardness 4 to 35.5, relative density 35.30 to 35.45, colourless to white to green to pink to blue colour, colourless streak. It is used as the main ingredient in zinc sun cream. Calamine, is used in pink calamine lotion for treating sunburn. Smithsonite, zinc carbonate, ZnCO3, is a widespread secondary mineral from the oxidized zones. It occurs as rounded botryoidal aggregates resembling drops of wax and as honeycombed masses in ore bodies. It is the most abundant secondary carbonate after cerussite. The associated minerals are coronadite and goethite. It is a widespread secondary mineral from the oxidized zones. The associated minerals are coronadite and goethite. It was formerly used to produce brass.
35.20.41 Sphalerite, ZnS
Sphalerite, zinc blende, blende. black jack, zinc iron sulfide (Zn, Fe)S, has black colour but other colours also occur, hardness 3.5 to 4, yellow to brown streak, diamond-like to submetallic lustre, good cleavage in 6 directions, relative density 35. The crystals may be transparent with brilliant sheen or translucent to opaque with metallic lustre. It may glow if crushed, triboluminescent. Zinc blende frequently occurs in compact masses with quartz, copper pyrites and galena. Zinc is used to galvanize iron for roofing, for lining iron "tins" to prevent rust and in the manufacture of white paint and optical glass. Note lustre, streak and softness of the specimen. Sphalerite (zinc sulfide, ZnS) is the main zinc ore mineral at Broken Hill. Good crystalline sphalerite is unusual at Broken Hill. The colour of sphalerite varies with its impurities. At Broken Hill it is black but some rare large crystals have a deep red colour.
35.20.42 Stibnite, Sb2S3
Stibnite, has grey to silver colour, hardness 2, dark grey streak, metallic lustre, cleavage in one direction and relative density 35.6. It can mark paper. The crystals are curved and twisted. It is the most important source of antimony. Antimony is an important metal in the printing industry.
Note the crystal habit of the specimen.
35.20.43 Stilbite
Stilbite, hydrated sodium calcium aluminium silicate, has more than one chemical formula, e.g. Na2,Ca,K2Al2Si7O18.7H2O, NaCa2Al5Si13O36.14H2O, has white to pink to yellow colour, hardness 3.5 to 4, white streak, glassy to pearly lustre, good cleavage in one direction, relative density 2.2. Note how thin crystals stick together like a sheaf of wheat, lustre and density of the specimen.
35.20.44 Sulfur, S
Sulfur has yellow crystals with colour sometimes masked by impurities, hardness 2, yellow streak, glassy lustre, poor cleavage, conchoidal fracture, and relative density 2. If held in a warm hand it may crackle, so it should be handled with care. It burns with a small blue flame to form sulfur dioxide. It is given off from volcanoes and deposited by the waters of some geysers and hot springs. Sulfur is used in the manufacture of sulfuric acid, insecticides, medicines, matches, gunpowder and fireworks. Note the colour, smell, and sensitivity to heat of the specimen.
35.20.45 Tin, Sn
Tin is very rare as native tin in placer deposits and tin is seldom used by itself. Bronze is approximately 5% tin and 95% copper. Other tin alloys include solder and pewter. Tin is used in the glass industry.
35.20.46 Uraninite, UO2
Uraninite, (with UO3, Th, Pb Pitch blende, Pitch ore), occurs usually as pitch-like masses (not crystals), has grey to black colour with brown tint, hardness 35.6, brown to black streak, metallic to dull lustre or a shine like pitch, poor cleavage, conchoidal to uneven fracture, and relative density between 7 and 10. It is moderately hard and very heavy. It undergoes radioactive decay to produce radium and helium, and other decay products. Uranium is used in special high grades of steel and is also the basic material used in atomic bombs and the world's nuclear power stations. It is a rare material but large deposits occur. Note the radioactivity, lustre, colour and streak of the specimen.
35.20.47 Uranium, U
Uranium occurs as uranium dioxide, UO2, in the mineral pitchblende, uraninite, that also contains radium and products of radioactive disintegration.
35.20.48 Wolframite
Wolframite, iron manganese tungstate (Fe, Mn)WO4, has grey to brown to black colour, hardness 4 to 35.5, brown to black streak, dull lustre, good cleavage in one direction, and relative density 7 to 7.35. Wolframite is an important ore of tungsten, W, used to increase the hardness of steel.
Note the cleavage, density and lustre of the specimen.
35.20.49 Zeolite
Zeolite, e.g. tetrapropylammonium (TPA) ZSM-5, is a group of natural or synthetic hydrated aluminium silicates that appear to boil when heated in a blowpipe. They retain pores or channels in their crystal structure, easily gain or lose water, and have a high ion exchange capacity. They are used in detergents as water softeners, and as catalysts for reforming petroleum products.
35.20.50 Zinc, Zn
Zinc is white to blue grey colour, hardness 2, grey streak, metallic lustre, good cleavage in one direction, relative density 6.9 to 7.2. It almost never occurs as the metal but combined with sulfur or oxygen. Zinc is brittle and must be heated to become malleable or ductile.
Note colour, hardness and density of the specimen. Zinc, Zn, occurs mainly as sphalerite (zinc sulfide, ZnS). At Broken Hill it has a black resinous appearance but rarely shows as big crystals. Smithsonite (zinc carbonate, ZnCO3), resulting from the weathering and oxidation of ore by groundwater, is found in areas where the ore body was at or near the surface. Zinc is used in galvanized coatings of iron and steel. It is also used in die cast alloy products, pigments and other industrial and agricultural applications.
35.20.51 Zincite
Zincite, red oxide of zinc, ZnO, is found in metamorphic weathered deposits.
35.20.52 Tanzanite
Tanzanite is found near Mount Kilimanjaro, Tanzania. It is a variety of the mineral zoisite, is heated to become a gemstone that exhibits trichroism, i.e. alternately sapphire blue, violet, and burgundy colours, depending on crystal orientation.
35.20.53 Ammolite
Ammolite, (aapoak, Kainah, gem ammonite, calcentine, korite), one of the rarest gemstones, is found in Alberta and on slopes of Rocky Mountains, is composed of fossilized shells of ammonites, mostly aragonite crystals as in nacrous pearl shell. The pearly flashes of red, green and blue iridescence from polished ammolite is caused by interference of light rebounding through layers of aragonite.
35.20.54 Nacre
Nacre, mother of pearl, pearls, an inner shell layer of some molluscs, is iridescent because of tiny plates of aragonite held within an organic matrix, e.g. chitin, that strengthens the nacre. It may produce a blister pearl attached to the interior of the shell, or a free pearl within the mantle tissues.
35.20.55 Lapis lazuli, ancient intense blue semi-precious stone, lazurite mineral (Na,Ca)8[(S,Cl,SO4,OH)2.(Al6Si6O24)], original source of deep blue pigment ultramarine (beyond the sea), often occurs in crystalline marble. This deep blue pigment much replaced by Prussian blue.
35.24.1 Make artificial igneous rocks, alum crystals, sulfur crystals
1. Crystallization of alum solutions is similar to the formation of coarse grained and fine grained igneous rocks. Fill a test-tube one quarter full of powdered potash alum, [Al2(SO4)3.K2(SO4).24H2O] [also shown as KAl(SO4)2.12H2O]. Slowly add just enough boiling water to dissolve the alum. Hold the test-tube in a flame so that the mixture boils gently. (a) Pour half the solution into a shallow metal container. Place a piece of string partly in the liquid and add a seed crystal. Stir the alum solution in the container so it cools quickly. (b) Hang another piece of string in the test-tube so that it reaches the bottom and add a seed crystal. Place the test-tube where it will cool slowly. Examine the two solutions the following day and note the sizes of the crystals formed.
2. Melt some sulfur in a test-tube. Fit a filter paper into a funnel and pour the molten sulfur into it. As the sulfur cools it begins to solidify, first forming a crust on the surface. As soon as the crust has formed, remove the filter paper from the funnel and unfold it, so that the still liquid sulfur in the lower part of the filter can flow away from the crust. Note a mass of small crystals on the underside of the crust. Use a magnifying glass to observe the shape of these crystals.
3. Melt sulfur in a test-tube then pour it into a large beaker of water so that it solidifies rapidly to form plastic sulfur. Take it out of the water and examine it after two hours. The solid sulfur formed is very hard and you cannot see crystals with a magnifying glass. However, very tiny crystals may be seen with a microscope.
35.24.2 Make artificial rocks, sedimentary rocks
1. Use a hammer to grind different coloured sedimentary rocks, keeping the colours separated. Put coloured powdered particles in a glass jar as different layers. Let water trickle down the inside of the jar so as not to disturb the layering until the water is 1 cm above the sediments. Put the jar in the sun and let the water evaporate. Wrap the jar in a thick cloth and break it with a hammer.
2. Mix Portland cement with water and put it in a mould until it hardens. Break the set cement with a hammer and examine the outside and inside surfaces.
3. Mix dry cement with twice as much sand or gravel to form concrete. Add water, mix thoroughly, and place it in a mould. Leave the concrete to harden for several days. Break the set concrete with a hammer and examine the outside and inside surfaces. Note whether the concrete is easier or harder to break than the Portland cement.
4. Mix plaster of Paris with a small amount of water and put it in a mould until it hardens. Stir rapidly or it will harden while being mixed. Break the set plaster with a hammer and examine the outside and inside surfaces. Note whether the plaster is easier or harder to break than the Portland cement or the concrete.
35.24.3 Make artificial rocks, metamorphic rocks
Fire a shaped piece of clay that has first been dried and put on a piece of broken pottery and heated it in a large crucible over a Bunsen burner.