14.1: Mineral Identification Tables

Color: Golden yellow, Luster: bright metallic, streak: greenish or brownish black/gray, D=4.9, H=6.25

Commonly forms cubic crystals, some may have striated faces. Commonly referred to as “Fool’s Gold”.

Color: Black to dark gray, Luster: pearly, Streak: black, D=5.2, H=5.5–6

May be attracted to a magnet or magnetized

Color: Silver or lead gray, Luster: bright metallic, Streak: gray, D=7, H=2.5

Three cleavage directions form cubes, high density

Color: steel gray, Luster: bright metallic, Streak: red, D=5.3, H=5–6

Commonly appears micaceous or foliated, some specimens may be slightly magnetic

Color: Dark brown to yellowish-brown, Luster: metallic to submetallic or resinous, Streak: brown or yellow, D=4, H=3.5–4

May smell slightly like sulfur when powdered on streak plate

Color: Black, Luster: Vitreous, Streak: White to gray or greenish gray, D=3.0-3.5, H=5.5

Cleavage more obvious when rotated in bright light

Color: medium green to greenish black, some sample light greenish gray, Luster: Vitreous, Streak: white to green, D=3.4, H=6

Commonly forms large blocky crystals, cleavage not always obvious

Color: greenish gray to black, Luster: Vitreous, Streak: White, D=2.7, H=6-6.5

Individuals crystals have striations on cleavage planes, some samples are iridescent, commonly occurs in coarsely crystalline aggregates

Color: Black, Luster: Vitreous, Streak: White, D=3-3.2, H=7-7.5

Looks superficially like hornblende, good samples form elongate striated prisms with triangular cross-sections

Color: most commonly red to brown, Luster: Vitreous; Streak: white; D = 3.1-4.3; H = 6.5-7.5

Color: most commonly red to brown, Luster: Vitreous; Streak: white; D = 3.1-4.3; H = 6.5-7.5

Color: red to gray, Luster: Earthy, Streak: Red, D=5.2, H=5-6

Red, rusty color with a drab luster.  

Color: Black to dark gray, Luster: pearly or submetallic, Streak: black, D=5.2, H=5.5-6

Color: Black to dark gray, Luster: pearly or submetallic, Streak: black, D=5.2, H=5.5-6

Color: olive green to army green, Luster: Vitreous, Streak: white to light green, D=3.2-4.4, H=6.5-7

Distinct green color, commonly forms granular crystalline masses

Color: Black, Luster: Vitreous to pearly (looks like plastic), Streak: White to gray, D=2.7-3.4, H=2.5-3

Perfect cleavage causes the specimen to break in to thin sheets

Color: Dark brown to yellowish-brown, Luster: metallic to submetallic or resinous, Streak: Brown or yellow,   D=4, H-3.5-4

May smell slightly like sulfur when powdered on streak plate

Color: Reddish brown, Luster: Vitreous to pearly, Streak: White, D=3.9, H=3.5-4.5

May react with HCl when powdered, often found as nodules in sedimentary rocks, may appear broadly similar to garnet or hematite.

Color: Pink to white to light gray, Luster: Vitreous to resinous, Streak: White, D=2.7, H=6-6.5

Cleavage planes show white exsolution lamellae that give it a fibrous look similar to muscle tissue

Color: light greenish gray to dark gray, Luster: Vitreous, Streak: White, D=2.7, H=6-6.5

Striations on cleavage planes in good samples

Color: medium green to greenish black, Luster: Vitreous, Streak: white to green, D=3.4, H=6

Commonly forms large blocky crystals, cleavage not always obvious, looks like a green feldspar

Color: clear, white, purple, pink, gray, Luster: Vitreous, Streak: white, D=2.6, H=7.

Conchoidal fracture, commonly forms large 6-sided crystals

Color: olive green to army green, Luster: Vitreous, Streak: white to light green, D=3.2-4.4, H=6.5-7

Distinct green color, commonly forms granular crystalline masses

Colors: Commonly green or purple, Luster: Vitreous, streak: white, D=3.2, H=4

Looks similar to quartz but does not scratch glass.

Color: White to clear, variety of other colors possible, Luster: vitreous to earthy, streak: white to gray, D=3, H=3

Effervesces vigorously in dilute HCl, commonly breaks into rhombohedrons, clear specimens may show double refraction

Color: Commonly white to clear, other colors possible, Luster: vitreous to pearly, streak: white to gray, D=2.9, H=3.5-4

Effervesces when powdered, commonly breaks into rhombohedrons, looks very similar to calcite

Effervesces when powdered, commonly breaks into rhombohedrons, looks very similar to calcite

Tastes like salt, three cleavage directions at 90° causes it to break in to small cubes

Color: Pale green to white or light gray, Luster: greasy to pearly, Streak: white, D=2.7, H=1.

Has a greasy or soapy feel

Color: white to light yellow or brown, Luster: vitreous to pearly (looks like plastic), Streak: white, D=2.8, H=2.5-3.5

Perfect cleavage causes the specimen to break in to thin sheets

Color: clear to white, Luster: vitreous, Streak: white, D=2.3, H=2

Color: White to clear, variety of other colors possible, Luster: vitreous to earthy, streak: white to gray, D=3, H=3

Effervesces vigorously in dilute HCl, commonly breaks into rhombohedrons, clear specimens may show double refraction

Color: Pale green to white or light gray, Luster: greasy to pearly, Streak: white, D=2.7, H=1.

Has a greasy or soapy feel

Color: bright yellow, Luster: Earthy to resinous, Streak: yellow to yellow-white, D=2, H=2

Distinctive yellow color, may form crystals

Colors: Commonly green, purple, or light blue, Luster: Vitreous, streak: white, D=3.2, H=4

Looks similar to quartz but does not scratch glass.