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Mineral Groups

Mineral Groups. Mineral Groups. Element Abundances. Silica (SiO 4 ) 4-. SILICATES. Common cations that bond with silica anions. All others: 1.5%. Mineral Groups. Non-ferromagnesian Silicates (K, Na, Ca, Al). Ferromagnesian Silicates (Fe, Mg). Oxides Carbonates

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Mineral Groups

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  1. Mineral Groups

  2. Mineral Groups Element Abundances Silica (SiO4)4- SILICATES Common cations that bond with silica anions All others: 1.5%

  3. Mineral Groups Non-ferromagnesian Silicates (K, Na, Ca, Al) Ferromagnesian Silicates (Fe, Mg) Oxides Carbonates Sulfides/sulfates Native elements

  4. Silicates Actinolite(Tremolite) Ca2(Mg,Fe)5Si8O22(OH)2 Subclass: Amphibole Streak: White Hardness: 5 – 6 Lustre: Vitreous Density: 3.0 - 3.4Habit: Aggregate of acicular grainsColours: Greenish - white Crystal System: Monoclinic Cleavage: Uneven Fracture: Subconchoidal Magnetism: None Reaction with HCl: None Identification in hand sample:Habit and colour are best indicators. Associations:Metamorphosed calcareous sediments Comments:Higher in Fe than tremolite.

  5. Silicates Antigorite(Serpentine) Mg3Si2O5(OH)4 Subclass: PhyllosilicateHardness: 2.5 - 3.5 Streak: White Density: 2.6 Lustre: Greasy or waxy Habit: Lath-shaped crystals.Colours: Shades of green Crystal System: Monoclinic Cleavage: Perfect basal Fracture: Splintery or conchoidal Magnetism: None Reaction with HCl: Unknown Identification in hand sample:Lustre, colour and habit are indicative. Associations:Formed by hydrothermal action of mafics and ultramafics. Associations may include talc, calcite, brucite, chlorite, magnetite and chromite.

  6. Silicates Augite (Ca,Na)(Mg,Fe,Al,Ti)(SiAl)2O6Subclass: PyroxeneHardness: 5.5 – 6 Streak: White or gray Density: 3.2 - 3.5 Lustre: Vitreous Habit: Small blocky grains.Colours: Dark-greeny black colour Crystal System: Monoclinic Cleavage: Good / Uneven Fracture: Uneven to conchoidal Magnetism: None Reaction with HCl: None Identification in hand sample:Colour, cleavage and hardness are indicative of a pyroxene. Augite has 2 cleavage planes at 90°. Associations:Found in mafic to ultramafic rocks, and in high-grade metamorphs. Industrial / ecomonic uses:None.

  7. Silicates Biotite K(Mg,Fe)3(AlSi3O10)(OH)2Subclass: PhyllosilicateHardness: 2 – 3 Streak: Colourless Density: 2.7 - 3.4 Lustre: Vitreous Habit: MicaceousColours: Brown, black, reddish brown Crystal System: Monoclinic Cleavage: Perfect basal Fracture: Uneven Magnetism: None Reaction with HCl: Very weak Identification in hand sample:Colour and habit Associations:A very common mineral found in igneous, metamorphic and sedimentary rocks. Industrial / ecomonic uses:Altered into vermiculite, biotite is used as an insulation material and as filler in certain building supplies.

  8. Silicates Chalcedony  (Micro/Cryptocrystalline Quartz) -- SiO2Subclass: FrameworkHardness: 7 Streak: White Density: 2.7 Lustre: Vitreous / almost waxy Habit: Aggregate of very tiny SiO2 grains.Colours: White/gray or any colour Crystal System: Hexagonal Cleavage: None Fracture: Conchoidal Magnetism: None Reaction with HCl: None Identification in hand sample:Identified by hardness and texture/habit. Associations:Abundant in felsic rocks. Industrial / ecomonic uses:Used for making glass and as a source of Silicon.

  9. Silicates Chlorite (Mg,Fe,Al)3(Si,Al)4O10(OH)2Subclass: PhyllosilicateHardness: 2 - 2.5 Streak: Greenish white to white Density: 2.6 - 3.3 Lustre: Vitreous to somewhat pearly, waxy, dull Colours: Greenish-black (typical) Crystal System: Monoclinic Cleavage: Perfect {001} Magnetism: None Reaction with HCl: None Identification in hand sample:Colour and its low hardness are distinguishing characteristics. Industrial / ecomonic uses:None, however chlorite schist sometimes does have ornamental uses.

  10. Silicates Chrysotile  (Serpentine) Mg3Si2O5(OH)4Subclass: PhyllosilicateHardness: 2.5 Streak: White Density: 2.5 Lustre: Silky Habit: FibrousColours: Shades of green Crystal System: Monoclinic Cleavage: None Fracture: Uneven Magnetism: None Reaction with HCl: Unknown Identification in hand sample:Habit and colour and most indicative properties. Associations:Found by hydrothermal alteration of mafics and ultramafics. Associated with talc, calcite, brucite, chlorite, magnetite and chromite. Industrial / ecomonic uses:Used in 98% of world's production of asbestos.

  11. Silicates Epidote Ca2(Fe,Al)3(SiO4)3(OH) Subclass: SorosilicateHardness: 6 – 7 Streak: White Density: 3.4 - 3.5 Lustre: Vitreous Habit: Aggregate of small grains, striated faces, small but visible crystalsColours: Greeny, yellow-green, black Crystal System: Monoclinic Cleavage: Perfect Fracture: Uneven Magnetism: None Reaction with HCl: None Identification in hand sample:Slight colour difference between this mineral and olivine, but only under magnification (where details in the crystals can be seen). Also indicitive is the presence of a cleavage plane. Associations:Common accessory mineral in many regional and contact metamorphed rocks, particularly in more iron-rich rocks. Industrial / ecomonic uses:Semiprecious gemstone

  12. Silicates Garnet  (Pyrope, Grossular, Almandine)(Mg,Fe,Ca)3Al2(SiO4)3 Hardness: 6.5 – 7 Streak: White Density: 3.8 Lustre: Vitreous Habit: Small, well-formed crystalsColours: Darker reddy colours Crystal System: Isometric Cleavage: None Fracture: Conchoidal Magnetism: None Reaction with HCl: None Identification in hand sample:Crystal habit, colour and hardness. Industrial / ecomonic uses:Abrasives (particularly sandpaper), semi-precious gemstone.

  13. Silicates HornblendeCa2(Mg,Fe)4Al(Si7Al)O22(OH,F)2 Subclass: AmphiboleHardness: 5 – 6 Streak: White or gray Density: 3.3 - 3.4 Lustre: Vitreous Habit: Intergrown crystals, prismatic character of grains.Colours: Black Crystal System: Monoclinic Cleavage: 2 at 56° and 124° Fracture: Uneven / conchoidal Magnetism: None Reaction with HCl: None Identification in hand sample:Prominent striations, prismatic crystals and angle on cleavages is distinguishing. Associations:Forms in igneous rocks, and in the metamorphic rock amphibolite. Industrial / ecomonic uses: Ornamental.

  14. Silicates Muscovite KAl2(AlSi3O10)(OH)2 Subclass: PhyllosilicateHardness: 2.5 – 4 Streak: Colourless Density: 2.8 - 2.9 Lustre: Vitreous Habit: MicaceousColours: Colourless, to white or gray Crystal System: Monoclinic Cleavage: Perfect basal Fracture: Uneven Magnetism: None Reaction with HCl: None Identification in hand sample:Colour and habit are best indicators. Industrial / ecomonic uses:Used in the electronics industry in the manufacture of capacitors, transistors, insulators and certain window types. Also used as a filler in building materials.

  15. Silicates Olivine  (Forsterite (Mg) and Fayalite (Fe))Mg2SiO4 - Fe2SiO4Subclass: NesosilicateHardness: 6.5 – 7 Streak: Colourless Density: 3.3 - 4.3 Lustre: Vitreous Habit: GranularColours: Pistachio green, greenish yellow brown Crystal System: Orthorhombic Cleavage: Imperfect Fracture: Conchoidal Magnetism: None Reaction with HCl: Very weak Identification in hand sample:Pistachio-green colour and granular habit. Associations:Mafic and ultramafic igneous rocks. Associated with Ca-plag, Industrial / ecomonic uses:Peridote (a translucent variety of olivine) is considered a 'gem' mineral. Also used as a refractory sand and infrequently as an abrasive.

  16. Silicates Orthoclase  KAlSi3O8Hardness: 6 - 6.5 Streak: White Density: 2.6 Lustre: Vitreous Habit: Polysynthetic twinningColours: Pinky-white Crystal System: Orthorhombic Cleavage: Perfect Fracture: Subconchoidal Magnetism: None Reaction with HCl: None Identification in hand sample:Colour and evidence of exsolution with plagioclase. Associations:Very common in granite, granodiorite, syenite and related felsic rocks.

  17. Silicates Quartz (crystal) SiO2Hardness: 7 Lustre: Vitreous / glassy Density: 2.7 Habit: Crystalline Colours: Clear transparent Crystal System: Hexagonal Cleavage: None Fracture: Conchoidal Magnetism: None Reaction with HCl: None Identification in hand sample:Hardness, translucency and colour are indicators.

  18. Silicates Talc Mg3Si4O10(OH)2Subclass: PhyllosilicateHardness: 1 Streak: White Density: 2.6 - 2.8 Lustre: Greasy Habit: Compact masses, often no crystals.Colours: White, or brownish, dark green, gray Crystal System: Monoclinic Cleavage: Perfect Fracture: Uneven Magnetism: None Reaction with HCl: Unknown Identification in hand sample:Mineral is very soft and are often compact masses. Colour is typical and varies to brown, green or gray.

  19. Silicates Topaz Al2SiO4(F,OH)2Hardness: 8 Streak: White Density: 3.5 Lustre: Glassy Habit: Prismatic crystalsColours: Almost brownish, any colour Crystal System: Orthorhombic Cleavage: Perfect Fracture: Subconchoidal Magnetism: None Reaction with HCl: None Identification in hand sample:Resembles quartz, but harder. Associations:Quartz Industrial / ecomonic uses:Gemstone

  20. Silicates Zircon (ZrSiO4) Hardness: 7.5 Streak: White Density: 4.6 - 4.7 Lustre: SubadamantineHabit: Excellent tetragonal prismsColours: Colorless, red, brown, yellow, green or gray Crystal System: Tetragonal Cleavage: Imperfect Fracture: Conchoidal Magnetism: None Reaction with HCl: Unknown Identification in hand sample:Excellent crystalline habit, density and streak/colour are indicative. Industrial / ecomonic uses:Source of zirconium and hafnium

  21. Carbonates Azurite ---Cu3(CO3)2(OH)2Hardness: 3.5 – 4 Streak: Lighter blue Density: 3.8 Lustre: Vitreous, earthy (fine grained) Habit: Fine grained coating or fracture filling on rockColours: Azure blue Crystal System: Monoclinic Cleavage: Perfect Fracture: Conchoidal Magnetism: None Reaction with HCl: Strong Identification in hand sample:Colour is reliable, association with malachite is also indicative. Associations:Common mineral in the near-surface oxidized portion of copper-bearing hydrothermal sulfide mineral deposits. Associated with malachite. Industrial / ecomonic uses:A minor ore of copper, also has ornamental uses. Sometimes a pigment (when powdered).

  22. Carbonates Aragonite ----CaCO3 Hardness: 3.5 – 4 Lustre: Vitreous Streak: White Habit: Stalactitic aggregate of crystals or grains. Colours: Colourless or white Crystal System: Orthorhombic Cleavage: Pinacoidal Fracture: Subconchoidal Magnetism: None Reaction with HCl: Strong Identification in hand sample:Stalactitic habit, hardness (greater than that of calcite) and colour. Associations:Occurs in carbonate-bearing blueschist metamorphic rocks. Associated with glaucophane, lawsonite, pumpellyite. Also forms at or near the surface in cave and hot spring deposits. Industrial / ecomonic uses:Same as calcite, however abundance is much much less than that of calcite, thus having little economic value.

  23. Carbonates Calcite (massive) CaCO3Hardness: 3 Density: 2.7Streak: White Lustre: VitreousHabit: Fine grained aggregates (massive)Colours: Colourless, white, gray, yellow-brown, pink, rose red Crystal System: Hexagonal Cleavage: Perfect rhombohedral Fracture: Subconchoidal Magnetism: None Reaction with HCl: Strong Identification in hand sample:Recognized by hardness and cleavage. Dolomite and aragonite have higher densities. Associations:Common as a cementing agent in clastic sediments, or as fossil fragments. Essential constituent of limestone. Industrial / ecomonic uses:Used in the manufacture of portland cement (quicklime). Also used as a pharmaceutical (antacids, calcium supplements).

  24. Carbonates Calcite (sparry)  (Iceland Spar) ---- CaCO3 Hardness: 3 Streak: White Density: 2.7 Lustre: Vitreous Habit: Large crystals, some exhibiting common twin striaeColours: White Crystal System: Hexagonal Cleavage: Perfect rhombohedral Fracture: Subconchoidal Magnetism: None Reaction with HCl: Strong Identification in hand sample:Hardness, crystal habit and twin striae are typical. Associations:Common as a cementing agent in clastic sediments or as fossil fragments. Industrial / ecomonic uses:Used in the manufacture of portland cement (quicklime) and in the pharmaceutical industry. Comments:The transparent variety is called "Iceland Spar".

  25. Carbonates Dolomite ---- CaMg(CO3)2 Hardness: 3.5 – 4 Streak: White Density: 2.85 Lustre: Vitreous Habit: Crystalline or aggregate, some with twin striae. Colours: Pinky/peach, white, gray, brown. Crystal System: Hexagonal Cleavage: Perfect rhombohedral Fracture: Subconchoidal Magnetism: None Reaction with HCl: Weak Identification in hand sample:Harder than calcite Associations:Major constituent of dolostone (aka dolomite). Industrial / ecomonic uses:Used in manufacture of portland cement.

  26. Carbonates Malachite ---- Cu2(CO)3(OH)2Hardness: 3.5 – 4 Streak: Pale green Density: 4.0 Lustre: Earthy Habit: Very fine grained coating on other rocks, almost looks like paint.Colours: Copper green Crystal System: Monoclinic Cleavage: Perfect Fracture: Subconchoidal Magnetism: None Reaction with HCl: Strong Identification in hand sample:Colour is primary indicator, as well as habit. Associations:Common in near-surface oxidized portions of copper bearing hydrothermal sulfide mineral deposits. Industrial / ecomonic uses:Used as a minor ore of copper and also has ornamental uses due to vivid green colour.

  27. Carbonates Siderite ---- FeCO3Hardness: 3.5 – 4 Streak: White Density: 4.0 Lustre: Vitreous Habit: Aggregate of crystals or grainsColours: Tan brown (typical) Crystal System: Hexagonal Cleavage: Perfect rhombohedral Fracture: Uneven Magnetism: None Reaction with HCl: Weak Identification in hand sample:Identified by colour and hardness. Associations:Produced by hydrothermal alteration of limestone. May also occur as concretionary or oolitic forms in clay ironstones. Industrial / ecomonic uses:Sometimes used as an iron ore. Also used in pigments where a red or brown colour is desirable.

  28. Halides Fluorite --- CaF2 Hardness: 4 Streak: White Density: 3.1 - 3.3 Lustre: Vitreous Habit: Crystals, usually cubicColours: Commonly colourless, blue, purple or green, but any is possible. Crystal System: Isometric Cleavage: Perfect octahedral Fracture: Conchoidal Magnetism: None Reaction with HCl: Unknown Identification in hand sample:Cubic crystals, hardness and colour indicative. Associations:Common in hydrothermal mineral deposits associated with sulfides, carbonates and barite. Industrial / ecomonic uses:Main source of fluorine (which is added to drinking water, toothpaste, used as a flux in industrial uses and as part of CFCs)

  29. Halides Halite  (Salt) --- NaCl Hardness: 2 Streak: White Density: 2.1 - 2.2 Lustre: Waxy Habit: Crystalline (cubic)Colours: Colourless or white if pure, any colour if not Crystal System: Isometric Cleavage: Cubic Fracture: Conchoidal Magnetism: None Reaction with HCl: None Identification in hand sample:Has a salty taste. Cubic cleavage and hardness are indicative for the less brave geologists. Associations:Abundant in marine evaporite deposits and may form beds hundreds to over a thousand meters thick. Associated minerals include calcite, dolomite, gypsum, anhydrite and sylvite.

  30. Hydroxide Limonite-- FeO(OH) Hardness: 5 - 5.5 Streak: Yellow-brown Density: 2.7 - 4.3 Lustre: Earthy Habit: Fine grained aggregate, powdery coating.Colours: Orange, yellow-brown Crystal System: Unknown Cleavage: None Fracture: Uneven Magnetism: None Reaction with HCl: Very weak Identification in hand sample:Colour is best indicator, followed by habit. Associations:Common weathering product of iron-rich rocks. Comments:The fine brownish coloured mineral is usually weathered goethite.

  31. Oxides Chromite (FeCr2O4)Hardness: 5.5 Streak: Brown Density: 4.5 - 4.8 Lustre: Metallic to pitchy Habit: Fine grained aggregate.Colours: Black Crystal System: Isometric Cleavage: None Fracture: Uneven Magnetism: Weak Reaction with HCl: Unknown Identification in hand sample:Resembles magnetite and ilmenite, but not very magnetic and has a more resinous lustre. Associations:Found in mafic and ultramafic igneous rocks such as gabbro, peridotite, dunite and pyroxenite as an accessory mineral. Industrial / ecomonic uses:Only ore mineral for chromium.

  32. Oxides Corundum (Al2O3) Hardness: 9 Streak: White Density: 4.0 - 4.1 Lustre: Vitreous to adamantine Habit: Well-formed crystalsColours: Any. White, gray or gray-blue, or red (ruby), blue (sapphire), yellow, green.  Crystal System: Hexagonal Cleavage: None Fracture: Conchoidal Magnetism: None Reaction with HCl: None Identification in hand sample:Hardness is best indicator, crystal habit is good too. Associations:Gem quality corundum comes from metamorphed limestone or dolostone (needs high Al concentrations, here presumably from detrital deposits) Industrial / ecomonic uses:Used as a gemstone. High-quality ruby can be more valuable than diamond. Corundum is also used as an abrasive in sandpaper, polishing compounds, etc.

  33. Oxides Hematite (massive)  -- (Fe2O3) Hardness: 5 – 6 Streak: Deep red Density: 5.3 Lustre: Earthy Habit: Very fine grained aggregate of red crystals.Colours: Deep red Crystal System: Hexagonal Cleavage: None Fracture: Subconchoidal Magnetism: Weak Reaction with HCl: Unknown Identification in hand sample:Deep red streak and earthy lustre are indicative. SG may also be indicative. Associations:Produced by weathering or hydrothermal alteration of iron-bearing minerals. May be found in some syenite, trachyte, granite and rhyolite. Industrial / economic uses:Important ore or iron, sometimes used as a gemstone. Comments:May become magnetic when heated.

  34. Oxides Hematite (specular)  (Fe2O3) Hardness: 5 – 6 Streak: Deep red Density: 5.3 Lustre: Metallic Habit: Micaceous/tabular habit.Colours: Steel gray Crystal System: Hexagonal Cleavage: None Fracture: Subconchoidal Magnetism: None Reaction with HCl: Unknown Identification in hand sample:Shining gray metallic lustre and deep-red streak are indicative. Associations:Produced by weathering and hydrothermal alteration of iron-bearing minerals. Industrial / ecomonic uses:Important ore of iron.

  35. Oxides Magnetite (Fe3O4) Hardness: 5.5 - 6.5 Streak: Black Density: 5.2 Lustre: Dull metallic to splendentHabit: Granular habit of fine grains. Some octahedral crystals may form.Colours: Black Crystal System: Isometric Cleavage: None Fracture: Subconchoidal Magnetism: Strong Reaction with HCl: Unknown Identification in hand sample:Highly magnetic. Habit and colour are also indicators. Associations:Very common accessory mineral found in a wide variety of igneous and metamorphic rocks, usually as small grains. Industrial / ecomonic uses:Mined for iron. Crushed magnetite also been used as aggregate to make high-density concrete for specialized applications, such as nuclear reactors.

  36. Oxides Pyrolusite (MnO2) Hardness: 2 - 6.5 Streak: Black Density: 5.1 Lustre: Earthy Habit: Massive, compact, columnar or fibrous. Prismatic crystals are rare. Sometimes forms as dendritic coatings on other rocks.Colours: Black Crystal System: Tetragonal Cleavage: Perfect Fracture: Uneven Magnetism: None Reaction with HCl: Very weak Identification in hand sample:Will leave sooty marks if touched. Associations:Found in bog and marine deposits Industrial / ecomonic uses:Manganese is used to colour bricks.

  37. Phosphates Apatite Ca5(PO4)3( OH,F,Cl) Hardness: 5 Streak: White Density: 3.1 - 3.2 Lustre: Vitreous, glassy Habit: MassiveColours: Grayish blue-green, or any. Crystal System: Hexagonal Cleavage: Poor Fracture: Conchoidal Magnetism: None Reaction with HCl: Weak Identification in hand sample:Colour, crystal habit and hardness are good indicators. Associations:Common accessory mineral in all environments. Industrial / ecomonic uses:Source of phosphate used in fertilizers and other industrial applications. Fluorine is also extractable from apatite. Comments:Same stuff as in bones and teeth.

  38. Sulfates Alabaster  (Gypsum) CaSO4- 2H2OHardness: 2 Streak: White Density: 2.3 Lustre: VitreousHabit: Granular / massive form of gypsumColours: Colourless or white (typical) Crystal System: Monoclinic Cleavage: Perfect Fracture: Splintery Magnetism: None Reaction with HCl: Weak Identification in hand sample:Identified by hardness and good cleavage. Associations:Common in marine evaporite deposits. Industrial / ecomonic uses:Modern use is in gypsum wallboard used in construction. Used as an ornamental stone and for sculpture due to its softness.

  39. Sulfates Barite (BaSO4) Hardness: 3 - 3.5 Streak: White Density: 4.5 Lustre: Vitreous Habit: Fine grained aggregatesColours: Colourless, white, gray, yellowish, brown, reddish, bluish or greenish Crystal System: Orthorhombic Cleavage: Perfect Fracture: Uneven Magnetism: None Reaction with HCl: None Identification in hand sample:High specific gravity is best indicator, colour and fracture are also helpful. Associations:Common in hydrothermal veins, associated with galena, sphalerite, pyrite, quartz, fluorite and carbonates. Industrial / ecomonic uses:Primary ore for barium, also used as an additive to drilling mud (because of high SG). Has over 2000 uses in industry.

  40. Sulfates Selenite(Gypsum) CaSO4- 2H2OHardness: 2 Streak: White Density: 2.3 Lustre: Vitreous Habit: Large crystalline habitColours: Colourless, clear Crystal System: Monoclinic Cleavage: Perfect Fracture: Splintery Magnetism: None Reaction with HCl: Weak Identification in hand sample:Single large crystals of gypsum, typified by hardness and transparency. Associations:Found in marine evaporites. Industrial / ecomonic uses:Used in gypsum wallboard.

  41. Sulfides Chalcocite (Cu2S) Hardness: 2.5 – 3 Streak: Blackish lead-gray Density: 5.5 - 5.8 Lustre: Dull metallicHabit: Chunky fracture, massive habit.Colours: Blackish lead-gray Crystal System: Monoclinic Cleavage: Indistinct Fracture: Conchoidal Magnetism: None Reaction with HCl: None Identification in hand sample:Black colour with sooty appearance on weathered surfaces and sectile character are distinctive. Bronze-yellow on fresh surfaces. Associations:Found in the supergene-enriched zone of copper-bearing hydrothermal sulfide deposits. Industrial / ecomonic uses:Mined as a source of copper.

  42. Sulfides Chalcopyrite (CuFeS2) Hardness: 3.5 – 4 Streak: Greenish black Density: 4.3 - 4.4 Lustre: Metallic Habit: Fine grained to massive aggregates.Colours: Brass yellow, may be tarnished and iridescent. Crystal System: Tetragonal Cleavage: Poor Fracture: Conchoidal Magnetism: None Reaction with HCl: Very weak Identification in hand sample:Distinctive brassy-green colour. Has a richer yellow colour than pyrite and a lower hardness. Associations:Most common copper-bearing mineral, found in many hydrothermal sulfide deposits. Often associated with galena, sphalerite, pyrite and other sulfides. Industrial / ecomonic uses:Mined for its copper which has innumerable industrial uses.

  43. Sulfides Galena (PbS)Hardness: 2.5 Streak: Lead gray Density: 7.6 Lustre: MetallicHabit: Excellent cubic cleavage, crystals usually very evidentColours: Lead gray Crystal System: Isometric Cleavage: Perfect cubic Fracture: Subconchoidal Magnetism: None Reaction with HCl: Weak Identification in hand sample:Gives off a rotten-egg smell in HCl, very high SG, very metallic lustre. Associations:Very common in hydrothermal sulfide deposits. Associated with sphalerite, pyrite, chalcopyrite, quartz, calcite, fluorite, and/or barite. Industrial / ecomonic uses:Main ore from which lead is extracted, also a source of silver.

  44. Sulfides Pyrite (crystalline) FeS2 Hardness: 6 - 6.5Density: 5.0 Lustre: Metallic Streak: Greenish/brownish black Habit: Perfect cubic crystalline habit. Colours: Bronze-yellow Crystal System: Isometric Cleavage: Good Fracture: Conchoidal Magnetism: Unknown Reaction with HCl: None Identification in hand sample:Colour, hardness, streak and habit are best indicators. Gives off sparks when struck with a hard metal object. Associations:Most common sulfide mineral, almost always present in hydrothermal deposits. Industrial / ecomonic uses:May be used as source of iron or sulfur, but not normally of economic value.

  45. Sulfides Stibnite (Sb2S3) Hardness: 2 Streak: Lead gray Density: 4.6 - 4.7 Lustre: MetallicHabit: Range from fine to medium grains to prismatic crystals (with longitudinal striations). Complex terminations, radiating acicular groups.Colours: Lead gray, black, iridescent tarnish Crystal System: Orthorhombic Cleavage: Perfect Fracture: Subconchoidal Magnetism: None Reaction with HCl: Weak Identification in hand sample:Colour and small subhedral crystals are indicators. Also rather soft. Associations:Forms in low-temperature hydrothermal veins, or is deposited from hot mineral springs. Industrial / ecomonic uses:Important source of antimony (Sb)

  46. Native Elements Copper (Cu) Hardness: 2.5 - 3 Streak: Same Density: 8.9 Lustre: Metallic Habit: Massive, platey or dendritic habit.Colours: Light rose on fresh surface, copper-red on tarnished surface Crystal System: Isometric Cleavage: None Fracture: Hackly Magnetism: None Reaction with HCl: Weak Identification in hand sample:Colour and metallic characteristics are diagnostic. Associations:Found associated with mafic volcanic rocks, formed by reaction between Cu-bearing solutions and Fe-bearing minerals. Associated minerals are cuprite, chalcocite, bornite, epidote, calcite, chlorite and zeolites. Industrial / ecomonic uses:Used as electrical wire due to electrical conductivity and relatively low price. Comments:Obviously a source of copper, however most copper in modern times is mined from sulfide minerals.

  47. Native Elements Graphite (C) Hardness: 1 – 2 Streak: Black Density: 2.1 - 2.3 Lustre: Dull metallic, greasy feel Habit: Fine grained aggregateColours: Silver-black Crystal System: Hexagonal Cleavage: Perfect basal Fracture: Uneven Magnetism: None Reaction with HCl: None Identification in hand sample:Softness and lustre are best indicators. Associations:Common in pelitic metamorphic rocks such as phyllite, slate and schist. Produced as a result of decomposition of organic material. Industrial / ecomonic uses:Used in pencil leads and as a dry lubricant. Comments:Due to its softness, graphite is usually quite messy!

  48. Reference Cupit, Kerry. Mineral 1.0. 10June2011. Online. http://www.spaceman.ca/mineral/index.php

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