| Names & Composition | Hardness | Specific Gravity | Luster | Fracture | Remarks |
| Actinolite Ca2(Mg,Fe)5Si8O22 (OH)2 (An amphibole, grading into tremolite with decreasing Fe) | 5.0-6.0 | 3.0-3.2 | Vitreous, pearly silky | Uneven, splintery | Bladed to acicular to fibrous. Brittle. Pale to dark green. CI. in 2 directions parallel length at 56° and 124°. Streak paler than body color. |
| Anhydrite CaSO4 | 3.0-3.5 | 3 | Vitreous, pearly | Uneven, splintery | Granular, fibrous, cleavable. Brittle 3 cleavages at 90°; 1 perf. with pearly luster, 2 less perf. Colorless to bluish or brownish gray. Streak white or grayish white. |
| Apatite Ca5(PO4)3(OH,F,Cl) Collophane is a cryptocrystalline variety; Table 2, Chap. 1) | 5 | 3.1-3.4 | Vitreous to greasy | Conchoidal, uneven | Granular, compact; also in columnar hex. crystals. Green, blue, aquamarine, white, colorless. Streak white. Brittle. |
| Azurite Cu3(OH)2(CO3)2 | 3.5-4.0 | 3.77 | Vitreous | Conchoidal | Usually complex crystalline; also earthy. Brittle. Light to dark blue. Streak blue, lighter than body color. |
| Barite BaSO4 | 3.0-3.5 | 4.5 | Vitreous inclining to resinous | Uneven | Tabular to columnar crystals; also massive, laminated, earthy. Brittle.1 perf. and 2 minor cleavages at 90°. White, gray, pale yellow, brownish. Streak white. |
| Biotite K(Mg,Fe)3(Al,Fe)Si3O10(OH,F)2 | 2.5-3.0 | 2.7-3.3 | Vitreous to submet; pearly on cl. | Foliated; massive scaly aggregates. Perf. cl. in 1 direction. Flakes elastic. Black, green, brown, even thinnest scales usually colored. | |
| Cassiterite SnO2 | 6.07.0 | 6.67.1 | Adamantine to sl. greasy | Subconch, uneven | Massive, columnar, fibrous. Brittle. Usually yellow to reddish brown; also brownish black and opaque. Streak white, gray, brown. |
| Cerargyrite (also called Chlorargyrite) AgCl | 1.5-2.5 | 5.5-5.6 | Resinous to adamantine | Uneven | Sectile, ductile, and very plastic; waxy. Usually gray, becoming purple on exposure to strong light. Mostly massive. May have other minerals adhering. |
| Cerussite PbCO3 | 3.0-3.5 | 6.55 | Adamantine to vitreous, or resinous | Conchoidal | Massive, compact, earthy; tabular. Very brittle. Colorless, white, gray. Streak colorless, white. Effervesces in dilute HNO3. |
| Cinnabar HgS | 2.0-2.5 | 8.09 | Adamantine to dull | Uneven, subconch | Rhombohedral tabular and columnar crystals; also earthy. Perf. cl. in 2 directions at 60° and 120°. SI. sectile. Scarlet to brownish red and lead-gray. Streak scarlet. |
| Columbite-Tantalite Series (Fe,Mn,Mg)(Nb, Ta)2O6 | 6.0-6.5 | 5.0-7.95 | Submetallic, greasy, dull | Subconch, uneven | Stout columnar, equant, massive. Grayish and brownish black, may tarnish irid. High Mn varieties may show reddish brown internal reflections. Transparent in thin splinters. Streak dark red to black. |
| Corundum Al2O3 | 9 | 4.0-4.1 | Adamantine to vitreous | Uneven, conch | Stout columnar to barrel-shaped crystals; in rounded grains; massive granular. Brittle. Usually grayish, but many other colors, sometimes gem quality. |
| Covellite CuS | 1.5-2.0 | 4.6-4.8 | Submet to dull | Uneven | Massive or spheroidal; rarely in hex. plates. Perfect cl. in 1 direction. Luster slightly pearly on cleavage surfaces. Streak lead-gray to black. |
| Crocidolite (asbestos form of Riebeckite) Na2Fe5Si8O22 | 5 | 3.0-3.4 | Silky, dull | Finely fibrous. Blue to bluish gray, leek-green, lavender. An amphibole. Forms a series with magnesioriebickite. | |
| Cryptomelane KMn8O16 | 6.0-6.5 | ca. 4.3 | Submet to dull | Conchoidal | Fine-grained compact masses; concentrically banded spheroids; cleavable masses. Steel gray to black. Apparent hardness may be as low as 1 in fibrous and cleavable masses. |
| Cuprite Cu2O | 3.5-4.0 | 6 | Adamantine, submet, earthy | Conchoidal, uneven | Massive, granular, earthy. Also in octahedra, cubes (often elongated). Brittle. Shades of red to nearly black. Streak brownish, red, shining. |
| Ferberite FeWO4 (High-Fe member of Wolframite series) | 4.0-4.5 | 7.5 | Metallic-adamantine | Uneven | Columnar to bladed groups; massive. Perf. cl. in 1 direction. Black. Weakly magnetic. Streak brownish black to black. |
| Fluorite CaF2 | 4 | 3.18 | Vitreous | Uneven | Granular, massive earthy. Perf. cl. in 4 directions at 70-1/2° and 109-1/2°. Brittle. Usually colorless, white, or pale green, blue, purple, yellow. |
| Garnet Group A3B2(SiO4)3 Where A = Ca,Mg,Fe,Mn and B = Al,Fe,Cr | 6.5-7.5 | 3.5-4.3 | Vitreous, resinous | Conchoidal, uneven | Complete crystals dodecahedral or trapezohedral; also granular, lamellar, compact. Usually red, pink, yellow, white, or brown. No cl. but may have parting at 60° and 90°. Streak white. For details on individual species, see texts. |
| Goethite FeO(OH) (see Limonite below) | 5.0-5.5 | 3.3-4.3 | Silky, dull, adamantinemetallic | Uneven | Massive, fibrous, columnar; earthy to ocherous. Crystals blackish brown; brittle. Massive varieties yellowish to reddish brown. Earthy varieties brownish yellow. May form pseudomorphs after pyrite. Streak brownish to orangish yellow. |
| Hematite Fe2O3 (See also Table 1) | 5.0-6.0 | 5.26 | Metallic to submet, to dull | Subconch, uneven | Crystals steel gray, brittle. Flakes may be translucent or show red internal reflections. May form pseudomorphs after pyrite, magnetite. Streak red to reddish brown. |
| Hornblende Complex Ca,Mg,Fe,Al silicate (an amphibole) | 5.0-6.0 | 2.9-3.45 | Submet, vitreous, pearly | Uneven, splintery | Columnar to fibrous. Perf. cl. in 2 directions parallel length, at 56° and 124°. Brittle. Dark green, black, brown. Translucent in thin splinters. Streak paler than body color. |
| Huebnerite MnWO4 (High Mn member of Wolframite series) | 4.0-4.5 | 7.12 | Submet, resinous | Uneven | Columnar, in radiating or parallel groups. Yellowish to reddish brown, rarely brownish black. Perf. cl. in 1 direction parallel length. Streak yellow to reddish brown. |
| Kyanite Al2SiO5 | 4.5 lengthwise 6.5 crosswise | 3.5-3.7 | Vitreous to pearly | Splintery | Bladed to columnar. 2 lengthwise cleavages at 74° and 106°. Usually white to blue, gradational. Rarely pale green. Streak white. |
| Limonite (2Fe2O3•3H2O) | 4.0-5.5 | 2.9-4.3 | Vitreous to dull | Uneven, earthy | Very brittle in vitreous forms. Compact, earthy, ocherous. Yellowish to reddish brown to brownish black. May be pseudomorphous after pyrite, siderite. Streak yellowish to reddish brown. |
| Magnesite MgCO3 | 4.0-4.5 | 2.98-3.4 | Vitreous to dull | Conchoidal | Granular, cleavable, compact like unglazed porcelain. Usually light-colored. Effervesces in hot dilute HCl. Streak nearly brown. |
| Malachite Cu2CO3(OH)2 | 3.5-4.0 | 3.6-4.1 | Adamantine to vitreous; silky dull | Uneven, subconch, splintery | Massive, fibrous, concentrically banded. 1 perfect cleavage. l. to d. green to blackish green. Efferv. in cold dilute acids. Streak pale green. |
| Monazite Rare earth phosphate | 5.0-5.5 | 4.6-5.7 | Resinous, waxy vitreous | Conchoidal, uneven | In sands, usually well rounded. Brittle. 2 cls. at 90°. Yellow, yellowish to reddish brown. Streak white or faintly colored. |
| Orpiment As2S3 | 1.5-2.0 | 3.49 | Resinous to greasy; pearly | Granular, foliated. 1 perf. cleavage. Cleavage lamellae flexible, show pearly luster. Lemon to golden and brownish yellow. Streak pale lemon-yellow. | |
| Psilomelane Hydrated Ba-bearing manganese mineral mainly Romanechite | 5.0-6.0 | 4.4-4.7 | Submet to dull | Often in concentric layers in rounded particles. Black. Streak black. In some specimens apparent H is down to 2. X-ray diffraction needed to distinguish from cryptomelane. | |
| Pyromorphite Pb5(PO4)3Cl | 3.5-4.0 | 6.57.0 | Resinous to greasy | Subconch to uneven | Crystals hex. prisms, often with hollow ends, or barrel-shaped. Granular, subcolumnar. Usually green, olive green, yellow, brown. Streak white. |
| Pyroxene Group Complex Ca,Mg,Fe,Mn,Al Silicates, some with Na, Ti | 5.0-6.5 | 3.0-3.96 | Vitreous, pearly, dull; some submet | Uneven | Massive, granular, lamellar, fibrous. Cl. in 2 directions near 90°. Brittle. Shades of gray, yellow, green, and brown. Streak grayish. |
| Realgar AsS | 1.5-2.0 | 3.5-3.6 | Resinous to greasy, dull | Conchoidal | Granular, compact, encrusting. Sectile. Transparent when fresh. Cleavage in 1 direction. Red to orange-yellow. Streak orange-red. |
| Rhodochrosite MnCO3 | 3.5-4.0 | 3.4-3.6 | Vitreous to pearly | Uneven | Granular to compact. 1 perf. cl. in 3 directions at 73° and 107°. Brittle. Usually in shades of pink to rose-red and reddish brown. Effervesces in hot dilute acids. |
| Ruby Silver Proustite (Ag3AsS3) and Pyrargyrite (Ag3SbS3) | 2.0-2.5 | 5.5-5.9 | Adamant | Conchoidal, uneven | Rhombohedral cl. distinct. May show red internal reflections. Scarlet to deep red or brownish red. Streak scarlet to purplish red. |
| Rutile TiO2 | 6.0-6.5 | 4.2-4.6 | Metallic-adamant | Conchoidal, uneven | Usually slender columnar to acicular. Brittle. Usually reddish brown, red, black. Streak pale brown to yellowish. |
| Scheelite CaWO4 | 4.5-5.0 | 5.9-6.10 | Vitreous to adamant | Uneven to subconch | Massive, granular. Brittle. Usually white, yellowish or brownish white. Fluoresces blue-white in short U.V. radiation. Streak white. |
| Siderite FeCO3 | 3.5-4.5 | 3.8-4.0 | Vitreous to pearly, dull | Conchoidal, uneven | Granular, cleavable, compact. Perf. cl. in 3 directions at 73° and 107°. Usually grayish and yellowish brown to brown and reddish brown. Effervesces in hot dilute acids. Streak white. |
| Sillimanite Al2SiO5 | 6.0-7.5 | 3.2-3.3 | Vitreous, silky | Splintery, uneven | Fibrous, columnar. Lengthwise cleavage in 2 directions at 88° and 92°. Brittle. Light brown, grayish brown, near-white, rarely pale green. Streak white. |
| Smithsonite ZnCO3 | 4.0-4.5 | 4.3-4.5 | Vitreous, pearly | Uneven, splintery | Granular to compact; earthy and friable. Perf. cl. in 3 directions at 72° and 108°. Brittle. Shades of gray, greenish to brownish white, yellow. Effervesces in cold dilute acids. Streak white. |
| Sphalerite (Zn,Fe)S | 3.5-4.0 | 3.9-4.1 | Resinous to adamant | Conchoidal | Perf. cleavage in 6 directions at 60°. Cleavable masses; granular, fibrous, cryptocrystalline. Brown, black, red, yellow, rarely green, white to nearly colorless. Streak brownish yellow to white. |
| Spodumene LiAlSi2O6 | 6.5-7.0 | 3.0-3.2 | Vitreous, pearly, dull | Splintery, uneven | Cleavable, compact, columnar. Cleavage in 2 directions at 87° and 93°. Greenish, grayish, and yellowish white; rarely pale green or purple. Streak white. |
| Tremolite Ca2Mg5Si8O22 (OH)2 (Low-Fe member of actinolite series) | 5.0-6.0 | 2.9-3.1 | Vitreous pearly, silky | Uneven, splintery | Bladed, columnar, fibrous, asbestiform. Brittle. Perf. cl. in 2 directions at 56° and 124° parallel length. White to gray. Streak white. |
| Uraninite UO2 | 5.0-6.0 | 6.5-10.6 | Submet, pitchlike to dull | Conchoidal, uneven | Massive, granular; cubic and octahedral crystals. Brittle. Steely to velvety and brownish black. Colloform varieties (pitchblende) may show banding. Streak brownish black, grayish. |
| Willemite Zn2SiO4 | 5.0-6.0 | 3.9-4.2 | Weak vitreous to resinous | Conchoidal, uneven | Columnar, massive, granular. Brittle. Greenish yellow, apple green, flesh red, grayish white, brown. Streak white or faintly colored. |
| Wolframite (Fe,Mn)WO4 (series between Huebnerite and Ferberite) | 4.0-4.5 | 7.0-7.5 | Metallic-adamant | Uneven | Columnar, lamellar, massive; granular. Dark grayish to brownish black. Brittle. 1 perf. cl. parallel length. May be slightly magnetic. Streak reddish brown to black. |
| Zincite (ZnMn)O | 4 | 5.4-5.7 | Subadamant | Conchoidal | Massive, foliated, compact, granular. Cleavage in 1 direction. Orange-yellow to deep red. Streak orange-yellow. |
| Zircon ZrSiO4 | 7.5 | 4.5-4.7 | Adamant | Uneven | Crystals square prisms with pointed ends. Commonly shades of brown, also colorless and orange. Brittle. Sometimes cloudy from its own radioactivity. Streak white. |