Augite (silicate)

Color: dark green to gray
Luster: nonmetallic
Hardness: 5.5-6
Streak: white to pale gray
Cleavage: good
Other Properties: forms 8-sided prisms, two cleave planes intersect at 87 and 93 degrees

Azurite (carbonate)

Color: deep blue
Luster: nonmetallic
Hardness: 3.5-4
Streak: light blue
Cleavage: ?
Other Properties: forms crusts of small crystals, opaque earthy masses, or short and long prisms

Biotite (mica)

Color: black, green-black, or brown-black
Luster: nonmetallic
Hardness: 2.5-3
Streak: gray-brown
Cleavage: excellent
Other Properties: forms very short prisms that split easily into very thin, flexible sheets

Calcite (carbonate)

Color: colorless, white, or yellow
Luster: nonmetallic
Hardness: 3
Streak: white
Cleavage: excellent
Other Properties: forms prisms, rhombohedrons, or scalenohedrons that break into rhombohedrons; effervesces in dilute HCl

Corundum (oxide)

Color: gray, blue, red, brown
Luster: nonmetallic
Hardness: 9
Streak: white
Cleavage: none
Other Properties: forms short hexagonal prisms with striated flat ends

Dolomite (carbonate)

Color: white, gray, cream, or pink
Luster: nonmetallic
Hardness: 3.5-4
Streak: white
Cleavage: excellent
Other Properties: breaks into rhombohedrons; effervesces in dilute HCl if powdered

Epidote (silicate)

Color: pale or dark green to yellow-green
Luster: nonmetallic
Hardness: 6-7
Streak: white
Cleavage: poor
Other Properties: massive or forms striated prisms

Fluorite (fluoride)

Color: colorless, purple, blue, gray, green, or yellow
Luster: nonmetallic
Hardness: 4
Streak: white
Cleavage: excellent
Other Properties: crystals usually cubes

Galena (sulfide)

Color: silvery gray
Luster: metallic
Hardness: 2.5
Streak: gray to dark gray
Cleavage: good
Other Properties: forms cubes and octahedrons

Garnet (silicate)

Color: red, black, or brown
Luster: transluscent to opaque
Hardness: 7
Streak: white
Cleavage: none
Other Properties: forms dodecahedrons, brittle

Graphite (carbon)

Color: metallic
Luster: metallic
Hardness: 1
Streak: dark gray
Cleavage: excellent
Other Properties: forms flakes, hexagonal prisms, and earthy masses

Gypsum (sulfate)

Color: colorless, white, or gray
Luster: transparent or transluscent
Hardness: 2
Streak: white
Cleavage: good
Other Properties: tabular crystals, prisms, blades, or needles

Halite (chloride)

Color: colorless, white, yellow, blue, brown, or red
Luster: transparent or transluscent
Hardness: 2.5
Streak: white
Cleavage: excellent
Other Properties: brittle, salty taste

Hematite (oxide)

Color: silvery gray, black, or brick red
Luster: metallic and earthy
Hardness: 5-6.5
Streak: red to red-brown
Cleavage: ?
Other Properties: forms thin tabular crystals or may be massive

Hornblende (amphibole)

Color: dark gray to black
Luster: nonmetallic
Hardness: 5.5
Streak: white to pale gray
Cleavage: good
Other Properties: forms prisms with good cleavage at 60 and 120 degrees, brittle

Kaolinite (clay)

Color: white to very light brown
Luster: nonmetallic
Hardness: 1-2
Streak: white
Cleavage: excellent but not visibl
Other Properties: forms earthy microcrystalline masses

Kyanite (aluminum silicate)

Color: blue, pale green, white, or gray
Luster: nonmetallic
Hardness: 4-7
Streak: white
Cleavage: ?
Other Properties: forms blades, transluscent to transparent

Magnetite (oxide)

Color: silvery gray to black
Luster: metallic
Hardness: 6
Streak: dark gray
Cleavage: none
Other Properties: forms octahedrons, attracted to magnet

Muscovite (mica)

Color: colorless, yellow, brown, or red-brown
Luster: nonmetallic
Hardness: 2-2.5
Streak: white
Cleavage: excellent
Other Properties: forms short opaque prisms, can be split into thin flexible transparent sheets

Olivine (silicate)

Color: pale or dark olive green to yellow or brown
Luster: nonmetallic
Hardness: 7
Streak: white
Cleavage: none
Other Properties: short cystals may resemble sand grains, conchiodal fracture

Orthoclase (feldspar)

Color: orange, brown, white, green, or pink
Luster: nonmetallic
Hardness: 6
Streak: white
Cleavage: excellent
Other Properties: forms transluscent prisms, exsolution lamellae

Plagioclase (feldspar)

Color: colorless, white, gray, or black
Luster: transluscent
Hardness: 6
Streak: white
Cleavage: good
Other Properties: striations, tubular crystals or blades, two cleavage directions at nearly 90 degrees

Pyrite (sulfide)

Color: brass yellow
Luster: metallic
Hardness: 6-6.5
Streak: dark gray
Cleavage: none
Other Properties: forms cubes or octahedrons, brittle

Quartz (silicate)

Color: colorless, white, or gray, many other varieties
Luster: greasy
Hardness: 7
Streak: white
Cleavage: none
Other Properties: forms hexagonal prisms and pyramids

Sphalerite (sulfide)

Color: yellow brown to brown or black
Luster: submetallic to non-metallic
Hardness: 3.5-4
Streak: white to pale yellow-bro
Cleavage: excellent
Other Properties: forms misshapen tetrahedroms or dodecahedrons

Staurolite (aluminum silicate)

Color: brown to gray-brown
Luster: nonmetallic
Hardness: 7
Streak: white to gray
Cleavage: poor
Other Properties: forms prisms that interpenetrate to form natural crosses

Sulfur (element)

Color: bright yellow
Luster: greasy to earthy
Hardness: 1.5-2.5
Streak: pale yellow
Cleavage: poor
Other Properties: forms transparent to transluscent crystals or earthy masses

Talc (silicate)

Color: white, gray, pale green, or brown
Luster: silky to greasy
Hardness: 1
Streak: white
Cleavage: none
Other Properties: forms cryptocrystalline masses that show no cleavage, feels greasy or soapy

Tourmaline (silicate)

Color: opaque black or green
Luster: nonmetallic
Hardness: 7-7.5
Streak: white
Cleavage: none
Other Properties: forms long striated prisms with triangular cross sections