Common Minerals

There are two keys to learning how to identify minerals and rocks: memorize their crucial diagnostic properties (given in bold face below) and see as many different examples as possible. Because rocks and minerals are so variable, the more examples you look at, the better you'll get at identifying rocks and minerals in the wild!

This page features an alphabetical list of minerals. There is also a page that matches the University of Pittsburgh's recitation rock kits and pages that group the main minerals found in igneous, sedimentary, and metamorphic rocks.

These pages assume you understand such properties as cleavage, fracture, streak, luster, hardness, etc.

Alphabetical List of Minerals



Physical Properties

Black to dark green; H = 5 to 6; D = 3.2 to 3.4; vitreous to dull luster; two imperfect cleavages meet at nearly 90°; a pyroxene mineral. Another pyroxene, diopside, is similar but is light grayish green.
Brown to brownish black; vitreous luster; H = 2.5 to 3.0; D = 2.8 to 3.2; may give a brown-gray streak; individual crystals are commonly small and cleavage surfaces are wavy; one perfect cleavage; transparent, flexible and elastic in thin sheets.
Clear, white, other colors less common; vitreous luster; H = 3; D = 2.7; three perfect cleavages form rhombohedric cleavage fragments; double image seen through clear pieces; reacts strongly with dilute hydrochloric acid.
Green to blackish green; dull to vitreous or pearly luster; H = 2 to 2.5; D = 2.6 to 3.3; may have faint green-yellow streak; cleavage flakes are flexible but not elastic; finely crystalline aggregates common.
Buff, gray, white, pinkish; H = 3.5 to 4; D = 2.8 to 2.9; small, rhombohedral crystals or massive; three cleavages not at 90°, may be indistinct; unless powdered, reacts slowly or not at all with dilute hydrochlorite acid.
Most commonly reddish brown or yellowish tan; vitreous to resinous luster; H = 6.5 to 7.5; D = 3.6 to 4.3; twelve-sided crystals (diamond-shaped faces) or roughly spherical crystals common. Broken surfaces may resemble cleavage in some large (> 1 cm) samples.
Clear, white, light gray; H = 2; D = 2.3; vitreous to pearly luster; may be able to flake off small brittle sheets; one perfect cleavage and two poor cleavages indicate the selenite variety of gypsum; alabaster is massive, satin spar is fibrous.
Clear to gray to red; H = 2.5; D = 2.2; three perfect cleavages meet at 90° (cleavage surfaces may be dull and partially dissolved after prolonged exposure); salty taste.
First variety: steel gray to dull red; H = 6; D = 5.0; red-brown streak; may be micaceous (tiny flakes) or massive.

Second variety: Red to reddish brown, H = 1.5 to 5.5; D = 5.0; dull luster; red-brown streak; earthy or oolitic (made of spherical structures 0.25 to 2 mm in diameter) masses.

Black; H = 5 to 6; D = 3.0 to 3.4; vitreous luster; may have faint green-gray streak; two perfect cleavages meet at 124° and 56°, but cleavage faces are commonly stepped rather than smooth; splintery appearance. An amphibole mineral.
Salmon-pink, white, gray, green; vitreous luster; H = 6; D = 2.5 to 2.6; two cleavages meet at nearly 90°; no striations.
White; H = 1 to 2.5; D = 2.6; dull luster; greasy feel, earth odor, powdery.
Light blue to greenish blue to blue-gray; vitreous luster; H = 5 parallel to long direction of crystal, H = 7 across crystal; blade-shaped crystals; one cleavage.
Colorless, silvery white, brownish silvery white; vitreous luster; H = 2.0 to 2.5; D = 2.8 to 2.9; one perfect cleavage; transparent, flexible, and elastic in thin sheets.
Olive-green to yellow green; vitreous to dull luster; H = 6.5 to 7 but often difficult to test because many samples are granular aggregates.
White to dark gray; sometimes buff; vitreous luster; H = 6; D = 2.6 to 2.8; two cleavages meet at nearly 90°; some cleavage faces have very fine, perfectly straight parallel striations, which show up in reflected light.
Brass-yellow; H = 6 to 6.5; D = 5.0; greenish black to black streak; massive or as crystals (cubes or pyritohedra).
Coarsely crystalline varieties: clear, milky, white, purple, smokey gray; pink; transparent to translucent; vitreous luster; H = 7; D = 2.7; conchoidal fracture; usually massive but six-sided crystals popular in rock shops; Microcrystalline varieties: chert(gray, dull luster), flint (black, dull luster), chalcedony (brown to gray, translucent, waxy luster), agate and onyx (varicolored bands, vitreous luster).
Multicolored green, black, gray; H = 3; D = 2.5 to 2.6; dull to greasy luster; slippery to slightly greasy feel; massive to fibrous (asbestos).
Red-brown to brownish black; vitreous, resinous, or dull luster; H = 7 to 7.5; D = 3.7; prismatic and X- or cross-shaped crystals.

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