Mineral Identification Tables
Table 1
Name H Color Streak Prominent Cleavage Composition Other Properties
Molybdenite 1 - 1.5 Lead-gray greenish to bluish gray YES - 1 dir. (platy) MoS2 Greasy feel; flexible plates
Graphite 1 steel-gray to black gray to black YES - 1 dir. (platy) C Greasy feel; flexible plates
Covellite 1.5 - 2 indigo-blue gray to black YES - 1 dir. (platy) CuS Iridescent yellow and red
Galena 2.5 Gray gray YES - 3 dir. at 90o PbS High specific gravity
Chalcocite 2.5 - 3 black to lead gray black to lead gray NO Cu2S Brittle, high specific gravity
Bornite 3 bronze, but with copper-red to purplish iridescence grayish black NO Cu5FeS4 Also known as peacock ore
Chalcopyrite 3.5 - 4 brassy yellow, usually tarnished greenish black NO CuFeS2 Softer than pyrite; most common copper mineral
Limonite (Goethite) 4 - 5.5 Yellow-brown, orange-brown, dark brown yellowish brown to reddish NO Goethite: HFeO2 Mixture of rust-like iron oxides. Mostly mineral "goethite." Earthy to metallic luster. Stalactitic, botryoidal forms common.
Hematite 5.5 - 6.5 Steel-gray to reddish brown reddish brown NO Fe2O3 Most common iron mineral; specular hematite variety is composed of fine silvery flakes
Magnetite 5.5 - 6.5 Black black NO (but sometimes shows parting) Fe3O4 Strongly magnetic; lodestone variety shows polarity; often in octahedral (8-sided) crystals
Pyrite 6 - 6.5 Pale brassy yellow greenish to brownish black NO FeS2 Known as "Fool's Gold." Brittle, common in crystals, but also granular and massive (no obvious form).
Name H Color Streak Luster Prominent Cleavage Composition Other Properties
Talc 1 green, white, gray white pearly or greasy YES - 1 dir. (Platy) Mg3Si4010(OH)2 Called "soapstone." Flexible plates, very soft
Sulfur 1 - 2.5 bright yellow yellow pearly none S low melting temperature
Realgar 1.5 - 2 red to orange orange-red resinous YES - 1 dir., GOOD AsS Sectile; yellow powder common on surface
Gypsum 2 colorless; white, gray, yellowish  white vitreous Only obvious in the selenite variety - 3 dir. (rhombic) CaSO4.2H2O 3 common varieties:
-selenite: clear, transparent
-satin spar: fibrous, silky
-alabaster: granular, sugary
Sylvite 2 - 2.5 Colorless, white, often reddish white vitreous YES - 3 dir. at 90o KCl Bitter taste 
Halite 2.5 Colorless, blue, yellow-blue white vitreous YES - 3 dir. at 90o NaCl Salty taste, dissolves easily in water
Biotite Mica 2.5 Black, dark green, or brown gray to white vitreous or pearly YES - 1 dir. (sheets) K(Mg,Fe)3
(AlSi 3O10)(OH)2
Flexible and elastic sheets
Muscovite Mica 2.5 Colorless, gray, or green white vitreous YES - 1 dir. (sheets) Kal2(AlSi 3O10) (OH)2 Flexible and elastic sheets
Bauxite 2 - 7 white to brown white earthy-dull NO Mixture of AlO(OH), Al(OH 3, and HAlO2 Mixture of 3 clay minerals:
Boehmite, Gibbsite, and Diaspore.
Earthy odor when breathed on.
Calcite 3 colorless or white; impurities may discolor it yellow or brown white vitreous YES - 3 dir., not at 90o (rhombic) CaCO3 Effervesces vigorously with cold dilute hydrochloric acid. Transparent calcite shows double refraction.
Barite 3 - 3.5 Colorless, white; impurities may discolor it brown, red, or yellow white vitreous YES - 2 dir. (seen in crystalline forms) BaSO4 High specific gravity (4.5). Ground-up barite is used as an weighting additive for drilling muds.
Dolomite 3 - 3.5 White, gray, brown, pink white vitreous to pearly YES, but not always obvious (rhombic).  CaMg(CO3 ) 2 Effervesces slowly with dilute cold hydrochloric acid, but only when powdered
Malachite 3.5 - 4 bright green pale green velvety, silky or dull Not obvious in rock masses Cu2(CO3)(OH)2 Effervesces in hydrochloric acid. Frequently in banded, botryoidal masses. Flame test produces green color.
Sphalerite 3.5 - 4  dark brown or black to yellow light yellow to brown resinous to sub-metallic YES - 6 dir. (all 6 directions not always obvious) ZnS Reacts with hydrochloric acid only when powdered to produce hydrogen sulfide gas.
Fluorite 4 colorless, white, yellow, purple, blue, green white vitreous YES - 4 dir. (all 4 directions not always obvious) CaF2 Cubic crystals common, 8-sided diamond-shaped crystals sometimes seen; often fluorescent 
Apatite 5 shades of yellow, green, blue, brown white vitreous Not obvious - indistinct Ca5(PO4) 3
Commonly seen as 6-sided prismatic crystals
Limonite (Goethite) 4 - 5.5 Yellow-brown, orange-brown, dark brown yellowish brown to reddish earthy, dull NO Goethite: HfeO2 Ordinary "rust" - a mixture of iron oxides, composed mostly of goethite.
Hematite 5.5.- 6.5 Red and reddish brown reddish brown dull to sub-metallic NO Fe2O3 Commonly appears in these forms: oolitic, botryoidal, or massive (no obvious form)
Augite (pyroxene) 6 dark green to black gray vitreous YES - 2 dir. at nearly 90o complex silicate Most common pyroxene; often appears as short, stubby, prismatic crystals in rock.
Hornblende (amphibole) 6 black, dark green, or brown grayish-white vitreous YES - 2 directions, ith angles at 56o and 24o complex silicate Most common amphibole; found in many igneous rocks. Characterized by dark, elongated crystals
Olivine 6 olive green or brownish white or gray vitreous to adamantine Not obvious - indistinct (Mg,Fe) 2 SiO4 Often found as "sugary" granular masses of dunite (olivine rock); gem variety called peridot
Plagioclase feldspar
(including Albite, Labradorite, etc.)
6 white to dark gray colorless or white vitreous YES - 2 dir. at nearly 90o NaAlSi3O8 to


Sodium-rich varieties are white or light gray; calcium-rich varieties are medium to dark gray. Labradorite variety shows blue play of colors.
Potassium feldspar
(Orthoclase, Microcline)
6 white, tan to orange, red, green, also colorless colorless or white vitreous or pearly YES - 2 dir. at nearly 90o KAlSi3O8 Most commonly found in granites and pegmatites. 
(crystalline varieties)
7 colorless, white, gray, purple, pink, black, yellow, green  colorless vitreous NO - shows conchoidal fracture SiO2 Varieties named by color:
Rock crystal (colorless), Milky (white), Smoky (gray), Amethyst (purple), Rose (pink), Citrine (yellow); 6-sided crystals common
(Chalcedony varieties)
7 all colors observed colorless waxy or dull usually NO - conchoidal fracture predominant SiO2 Collectively called "chalcedony" Agate (banded), Jasper (red or brown), Chert or Flint (white, gray or black)
Garnet group
(Almandine, etc.) 
7 - 7.5 commonly red and brown; also yellow, pink, green, black colorless to pale brown vitreous or resinous NO - but sometimes shows parting silicates of Al, Ca, Mg, Ge, Mn, Cr Commonly found in metamorphic rocks (transformed from plagioclase); 12-sided (dodeca-hedral) crystals are common
Tourmaline 7 - 7.5  black; also green, pink, brown colorless vitreous Not obvious - indistinct complex silicate of B, Al, Fe, Mg Common in 3-sided crystals, often prismatic with striations or columnar structure 
Corundum 9 gray, brown, blue, red, colorless colorless dull, vitreous, adamantine NO - but common shows parting Al2O3 Often in barrel-shaped crystals.
Clear gem varieties include:
-ruby (red)
-emerald (green)
Granular form is called emery