| Name | Refractive index | Birefringence | Optic sign | Optical character | Hardness | Specific gravity | Luster | Colors |
|---|---|---|---|---|---|---|---|---|
| Sellaite | 1.378–1.390 | 0.012 | Positive | U | 5 to 6 | 3.15 | Vitreous | Colorless to white |
| Fluorite | 1.434 | — | — | I | 4 | 3.18 | Vitreous | All Colors |
| Fire opal | 1.435 to 1.455 | — | — | — | — | 1.97 to 2.06 | Subvitreous to waxy | Colorless, white, yellow, red, orange, green, brown, black, blue, pink |
| Opal | 1.44 to 1.46 | — | — | I | 5.5 to 6 | 1.98 to 2.20 | Subvitreous to waxy | Colorless, white, yellow, red, orange, green, brown, black, blue, pink |
| Silica glass | 1.46 | — | — | I | 6 | 2.21 | — | — |
| Creedite | 1.460–1.485 | 0.025 | — | B | 3.5 | 2.71 | Vitreous | Colorless, white, violet, orange |
| Thaumasite | 1.464– 1.500 to 1.468–1.507 | 0.031 to 0.043 | Negative | U | 3.5 | 1.88 to 1.90 | Vitreous to silky | Colorless, white, pale yellow |
| Sodalite | 1.48 | — | — | I | 5.5 to 6 | 2.15 to 2.35, usually 2.25 to 2.3 | Dull vitreous to greasy | Rich royal blue, green, yellow, violet, white veining common |
| Natrolite | 1.480–1.493 | 0.013 | Positive | B | 5.5 | 2.20 to 2.25 | Vitreous, Silky, Pearly | White, colorless, sometimes pink |
| Obsidian | 1.48 to 1.51 | — | — | I | 5 | 2.33 to 2.42 | Vitreous | Deep black or blackish green |
| Moldavite | 1.48 to 1.54 | — | — | I | 5.5 | 2.34 to 2.39 | Vitreous | Mossy green |
| Calcite | 1.486 –1.658 | 0.172 | Negative | U | 3 | 2.71 | Vitreous to pearly on cleavage surfaces | Colorless or white, also gray, yellow, green, |
| Calcite(marble) | 1.486– 1.658 | — | — | — | 3 | 2.71 | Vitreous to pearly on cleavage surfaces | Colorless or white, also gray, yellow, green, |
| Coral | 1.486 to 1.658 | 0.172 | — | — | 3.5 | 2.6 to 2.7 | Opaque | White, Pink, Red, Black |
| Analcime | 1.487 | — | — | I | 5 to 5.5 | 2.20 to 2.29 | Vitreous | White, colorless, gray, pink, greenish, yellowish |
| Whewellite | 1.490 –1.650 | 0.16 | Positive | B | 2.5 | 2.23 | Vitreous, Pearly | White, yellow, brown, |
| Tektites | 1.49 to 1.53 | — | — | I | 5 | 2.36 to 2.51 | — | — |
| Yugawaralite | 1.492 –1.504 | 0.009 | Positive | B | 4.5 | 2.19 to 2.22 | Vitreous, Pearly | Colourless, white |
| Celluloid | 1.495 –1.510 | — | — | I | 1.5 | 1.36 to 1.42 | — | — |
| Cellulose Acetate | 1.495–1.505 | — | — | — | 1.5 | 1.29 to 1.40 | — | — |
| Celluloid | 1.495 to 1.510 | — | — | I | 1.5 | usually 1.36 to 1.80, 1.36 to 1.42 | — | — |
| Haüyne | 1.496 | — | — | I | 5.5 to 6.5 | 2.4 | Vitreous to greasy | Blue, white, gray, yellow, green, pink |
| Tugtupite | 1.496–1.502 | 0.006 | Positive | U | 6 | 2.36 to 2.57 | Sub-Vitreous, Waxy, Greasy, Dull | Commonly red, also white to pink, bluish white, greenish white |
| Perspex | 1.5 | — | — | I | 2 | 1.18 to 1.19 | — | — |
| Lapis lazuli | 1.5 | — | — | I | 5.5 | 2.70 to 2.90 | dull | Blue, mottled with white calcite and brassy pyrite |
| Mesolite | 1.50 (mean) | 0.001 | Positive | B | 5 | 2.29 | Vitreous, silky when fibrous | Colorless, white, gray, yellowish brown |
| Dolomite | 1.502– 1.681 | 0.179 | Negative | U | 3.5 to 4 | 2.8 to 2.9 | Vitreous to pearly | White, gray to pink |
| Petalite | 1.504–1.516 | 0.012 | Positive | B | 6 to 6.5 | 2.39 to 2.46 | Vitreous, pearly on cleavages | Colorless, grey, yellow, pink, to white |
| Ulexite | 1.51 (mean) | 0.02 | Positive | B | 1 | 1.65 to 2.00 | Vitreous; silky or satiny in fibrous aggregates | Colorless to white |
| Leucite | 1.51 (mean) | 0.001 | Positive | U | 5.5 to 6 | 2.45 to 2.50 | Vitreous | White to grey |
| Cancrinite | 1.51 (mean) | 0.022 | Negative | U | 6 | 2.42 to 2.50 | Vitreous, greasy, pearly | Grey-green, white, yellow, blue, orange, reddish |
| Poudretteite | 1.511 to 1.532 | 0.021 | Positive | U | 5 | 2.51 | Vitreous (Glassy) | Colorless, Light pink |
| Scolecite | 1.512–1.523 | 0.011 | Negative | B | 5 to 5.5 | 2.21 | Vitreous, silky when fibrous | Colorless white, pink, salmon, red or green |
| Magnesite | 1.515– 1.717 | 0.202 | Negative | U | 3.5 to 4.5 | 3.00 to 3.12 | Vitreous | Colorless, white, pale yellow, pale brown, faintly pink, lilac-rose |
| Pollucite | 1.517 to 1.525 | — | — | I | 6.5 | 2.85 to 2.94 | Vitreous to greasy | Usually colorless, also white, grey, pink, blue or violet |
| Sanidine | 1.518–1.524 | 0.006 | Negative | B | — | 2.57 to 2.58 | Vitreous, pearly on cleavage | Colorless to white |
| Thomsonite | 1.52–1.54 | 0.028 | Positive | B | 5 to 5.5 | 2.3 to 2.4 | vitreous, pearly | colorless, white, beige,and pink |
| Orthoclase feldspar (moonstone) | 1.52–1.53 to 1.53–1.54 | 0.008 | Negative | B | 6 | 2.56 to 2.59 | Vitreous, pearly on cleavage surfaces | Colorless, greenish, greyish yellow, white, pink |
| Stichtite | 1.52–1.55 | 0.027 | Negative | U | 2.5 | 2.15 to 2.22 | Waxy to resinous | Lilac to rose-pink |
| Gypsum (alabaster) | 1.52–1.53 | 0.01 | Positive | B | 1.5 to 2 | 2.30 to 2.33 | Vitreous to silky, pearly, or waxy | Colorless to white; may be yellow, tan, blue, pink, brown, reddish brown or gray due to impurities |
| Microcline feldspar | 1.522–1.530 | 0.008 | Negative | B | 6.5 | 2.56 to 2.58 | Vitreous | Colorless |
| Yellow orthoclase feldspar | 1.522–1.527 | 0.005 | Negative | B | 6 | 2.56 | Vitreous | Green, Yellow |
| Milarite | 1.529–1.532 to 1.548–1.551 | 0.003 | Negative | U | 5.5 to 6 | 2.46 to 2.61 | — | — |
| Lepidolite | 1.530–1.556 | 0.026 | Negative | B | 3.5 to 4 | 2.8 to 3.3 , usually 2.80 to 2.9 | Vitreous to pearly | Pink, purple, rose-red, violet-gray, yellowish, white, colorless |
| Iolite | 1.53–1.54 to 1.54–1.55 | 0.008 to 0.012 | Negative | B | 7 | 2.57 to 2.66,usually 2.57 to 2.61 | Greasy or vitreous | Blue, smoky blue, bluish violet; greenish, yellowish brown, gray; colorless to very pale blue in thin section |
| Aragonite | 1.530– 1.685 | 0.155 | Negative | B | 3.5 to 4 | 2.93 to 2.95 | Vitreous, resinous on fracture surfaces | White, red, yellow, orange, green, purple, grey, blue and brown |
| Amazonite | 1.52 to 1.53 | 0.008 | Negative | — | 6 to 6.5 | 2.56 to 2.58 | Vitreous | Blue, Green, Purple, Gray, Multicolored |
| Meerschaum | 1.53 (mean) | — | — | — | 2 | 1.00 to 2.00 | — | — |
| Chalcedony | 1.530 to 1.539 | 0.004 (av.) | Negative | B | 7 | 2.58 to 2.62 | Waxy, vitreous, dull, greasy, silky | Various |
| Pearl | 1.530 to 1.685 | 1.55 | — | — | 3.5 to 4 | 2.20 to 2.78 | — | white, pink, silver, cream, brown, green, blue, black, yellow, and purple |
| Witherite | 1.532–1.680 | 0.148 | Negative | B | 3.5 | 4.27 to 4.35 | Vitreous, resinous on fractures | Colorless, white, pale gray, with possible tints of pale-yellow, pale-brown, or pale-green |
| Apophyllite | 1.535–1.537 | 0.002 | Pos/Neg | U | 4.5 to 5 | 2.30 to 2.50 | Vitreous; pearly | Usually white, colorless; also blue, green, brown, yellow, pink, violet |
| Bone | 1.54 | — | — | — | 2.5 | 2 | — | — |
| Copal resin | 1.54 | — | — | I | 2 | 1.03 to 1.10 | — | — |
| Vegetable ivory | 1.54 | — | — | — | 2.5 | 1.38 to 1.42 | — | — |
| Dentine ivory | 1.54 | — | — | — | 2.25 to 2.5 | 1.70 to 1.98 | — | — |
| Amber | 1.54 | — | — | I | 2 to 2.5 | 1.03 to 1.10 | ||
| Nepheline | 1.54 | 0.004 | Negative | U | 5.5 to 6 | 2.55 to 2.65 | Vitreous - greasy | White, Gray, Brown, Brownish gray, Reddish white |
| Albite feldspar | 1.54 approx. | 0.011 | Positive | B | 6 to 6.5 | 2.62 | Vitreous, typically pearly on cleavages | White to gray, blueish, greenish, reddish; may be chatoyant |
| Soapstone | 1.54 approx. | — | — | B | 1 to 2 | 2.7 to 2.8 | — | — |
| Jasper | 1.54 approx. | — | — | — | 7 | 2.58 to 2.91 | Vitreous | White, Blue, Red, Green, Yellow, Orange, Brown, Gray, Black, Banded, Multicolored |
| Oligoclase feldspar (sunstone) | 1.542–1.549 | 0.007 | Negative | B | 6 to 6.5 | 2.62 to 2.65 | Vitreous. Pearly on cleavage surfaces. | Colorless, yellow, red, green, blue, and copper shiller |
| Quartz | 1.544–1.553 | 0.009 | Positive | U | 7 | 2.65 | Vitreous – waxy to dull when massive | Colorless through various colors to black |
| Scapolite (pink | 1.544–1.560 | 0.016 | Negative | U | 6 | 2.63 | Vitreous | White, Colorless, Yellow, Orange, Brown, Pink, Purple |
| Scapolite (yellow) | 1.548–1.568 | 0.02 | Negative | U | 6 | 2.71 | Vitreous | White, Colorless, Yellow, Orange, Brown, Pink, Purple |
| Tortoise-shell and horn | 1.55 | — | — | — | 2.5 | 1.26 to 1.35 | — | — |
| Charoite | 1.550–1.559 | 0.009 | Positive | B | 5 to 6 | 2.54 to 2.68 | Vitreous to pearly | Violet, lilac, light brown |
| Pyrophyllite | 1.55– 1.60 | — | — | — | 1.5 | 2.8 | Pearly to dull | Brown green, brownish yellow, greenish, gray green, gray white |
| Saussurite | 1.55–1.70 | — | — | — | 6.5 | 2.7 to 3.4 | — | — |
| Casein (protein plastic) | 1.55 to 1.56 | — | — | I | 2.5 | 1.32 to 1.34 | — | — |
| Casein plastic | 1.55 to 1.56 | — | — | I | 2.25 | 1.32 to 1.34 | — | — |
| Hambergite | 1.553 –1.625 to 1.559–1.631 | 0.072 | Positive | B | 7.5 | 2.35 | Vitreous | Colorless, pale gray, pale yellow |
| Beryllonite | 1.553–1.562 | 0.009 | Negative | B | 5.5 to 6 | 2.80 to 2.85 | Vitreous to adamantine, may be pearly on {010} | Colorless, white to pale yellow |
| Synthetic emerald (flux melt) | 1.558–1.563 | 0.003 | Negative | U | 7.5 | 2.65 | Opaque | Black |
| Black coral | 1.56 | — | — | — | 3.5 | 1.34 | — | — |
| Deer horn | 1.56 | — | — | — | 2.5 | 1.60 to 1.85 | — | — |
| Serpentine (bowenite) | 1.56 | — | Negative | B | 2.5 to 4 | 2.5 to 2.7, 2.58 to 2.62 | Greasy, waxy, or silky | White, yellow, green, gray, brown, black, purple; sometimes multicolored, especially green and yellow. |
| Labradorite feldspar (yellow) | 1.560–1.568 to 1.565–1.573 | 0.008 | Positive | B | 6 to 6.5 | 2.68 to 2.69 | Vitreous to pearly on cleavages | Gray, brown, greenish, blue, yellow, colorless |
| Emerald | 1.56–1.57 to 1.59–1.60 | 0.006 to 0.007 | Negative | U | 7.5 | 2.69 to 2.75 | Vitreous | Green shades to colorless |
| Variscite | 1.56 (mean) | — | Negative | B | 5 | 2.4 to 2.6 | Vitreous to waxy | Green, blue green, yellow green and rarely red |
| Brazil (some) | 1.566–1.571 | 0.005 | — | — | — | 2.69 | — | — |
| Bytownite feldspar | 1.567–1.576 | 0.009 | Negative | B | 6 to 6.5 | 2.73 | Vitreous, pearly on cleavages | Colorless, white, gray |
| Pseudophite | 1.57 | 0.003 | Pos/Neg | B | 2.5 | 2.60 to 2.85 | — | — |
| Serpentine (williamsite) | 1.57 | — | Negative | B | 2.5 | 2.61 | Greasy, waxy, or silky | White, yellow, green, gray, brown, black, purple; sometimes multicolored, especially green and yellow. |
| Aquamarine | 1.570–1.575 to | 0.005 to 0.006 | Negative | U | 7.5 | 2.68 to 2.73 | Vitreous | Blue |
| Odontolite | 1.57– 1.63 | — | — | Vitreous | 5 | 3.00 to 3.10 | — | — |
| Ophicalcite(Connemara marble) | 1.57 approx. | — | — | — | 3 to 4 | 2.7 approx. | — | — |
| Bastite | 1.57 to 1.58 | — | Negative | B | 3.5 to 4 | 2.5 to 2.7 | — | — |
| Colombia (Chivor) | 1.571–1.577 | 0.006 | — | — | — | 2.69 | — | — |
| Anhydrite | 1.571 –1.614 | 0.043 | Positive | B | 3 to 3.5 | 2.90 to 2.98 | Pearly on {010} vitreous to greasy on {001} vitreous on {100} | Colorless to pale blue or violet if transparent; white, mauve, rose, pale brown or gray from included impurities |
| Augelite | 1.574–1.588 | 0.014 | Positive | B | 5 | 2.7 | Vitreous, pearly on {110} cleavage | Colorless to white, may be yellowish to pale rose, greenish |
| Colombia (Muzo) | 1.578–1.584 | 0.006 | — | — | — | 2.71 | — | — |
| Tanzania | 1.578–1.585 | 0.007 | — | — | — | 2.74 | Vitreous, pearly on cleavage surfaces | Blue, Violet |
| yellow and some pink beryls | 1.580–1.586 | — | — | — | — | 2.68 to 2.73 | Vitreous to resinous | Green, blue, yellow, colorless, pink and others |
| Some white and pink beryls | 1.58–1.59 to1.59–1.60 | 0.008 to 0.009 | Negative | U | 7.5 | 2.80 to 2.90 | Vitreous to resinous | Green, blue, yellow, colorless, pink and others |
| Vivianite | 1.580– 1.627 | 0.047 | Positive | B | 2 | 2.6 | Vitreous, pearly on the cleavage, dull when earthy | Colorless, very pale green, becoming dark blue, dark greenish blue, indigo-blue, then black with oxidation |
| Verdite | 1.58 (mean) | — | — | — | 3 | 2.80 to 2.99 | Vitreous, silky, pearly | Green |
| Russia and Brazil | 1.581–1.588 | 0.007 | — | — | — | 2.74 | — | — |
| Catapleiite | 1.582– 1.627 | 0.028 | Positive | U | 6 | 2.73 to 2.90 | Vitreous, Dull | Dark brown, reddish brown, flesh red, yellowish red,colourless, light grey, beige to tan, light yellow, orange, light blue |
| Xonotlite | 1.583–1.593 | 0.01 | Positive | B | 5 to 6 | 2.7 | Vitreous - Silky | Colorless, Gray, Lemon white, Light gray, Pink. |
| Zambia | 1.583–1.590 | 0.007 | — | — | — | 2.74 | — | — |
| Habachtal | 1.584–1.591 | 0.007 | — | — | — | 2.74 | — | — |
| India | 1.585–1.595 | 0.007 to 0.010 | — | — | — | 2.73 to 2.74 | — | — |
| Zimbabwe | 1.586–1.593 | 0.007 | — | — | — | 2.75 | — | — |
| Transvaal | 1.586–1.593 | 0.007 | — | — | — | 2.75 | — | — |
| Colemanite | 1.586 –1.614 | 0.028 | Positive | B | 4.5 | 2.42 | Vitreous | Colorless, white, yellowish, grey |
| Pakistan | 1.588–1.595 | 0.006 | — | — | — | 2.76 | — | — |
| Polystyrene | 1.59 | — | — | I | 2.25 | 1.05 | — | — |
| Larimar | 1.59 to 1.65 | 0.038 | — | — | 4.5 to 6 | 2.70 to 2.90 | Silky | White, blue, green-blue, multicolored |
| Howlite | 1.59 (mean) | 0.02 | Negative | B | 3.25 | 2.58 | Subvitreous, glimmering | Colorless, Gray, White |
| Melinophane | 1.593– 1.612 | 0.019 | Negative | U | 3.5 | 3 | Vitreous | Colorless, shades of yellow. reddish. |
| Phosphophyllite | 1.595– 1.616 | 0.021 | Positive | B | 3.5 | 3.1 | vitreous | blue-green to colourless |
| Pectolite | 1.595 –1.633 | 0.038 | Positive | B | 5 to 6 | 2.62 to 2.88 | Silky, vitreous | Colorless, whitish, grayish, yellowish |
| Wardite | 1.595 (mean) | 0.009 | Positive | U | 5 | 2.81 | Vitreous | White, colorless, pale green, blue-green, yellow-green, pale yellow, yellow pink. |
| Ekanite | 1.597 | — | — | I | 6 to 6.5 | 3.28 | Vitreous | Green, yellow, dark red |
| Eudialyte | 1.598– 1.602 to 1.610–1.611 | 0.004 | Positive | U | 5 to 6 | 2.8 to 3.1 | Vitreous | Red, magenta, brown; also blue and yellow |
| Termolite | 1.599 to 1.637 | 0.026 | Negative | B | 5 to 6 | 2.99 to 3.03 | Vitreous and silky | White, gray, lavender to pink, light green, light yellow |
| Nephrite | 1.60–1.63 to 1.62–1.65, mean 1.62 | 0.027 | Negative | B | 6.5 | 2.90 to 3.02 | dull | Translucent to opaque and often mottled. Light to dark green, yellow to brown, white, gray, black. |
| Rhodochrosite | 1.60 –1.82 | 0.22 | Negative | U | 4 | 3.50 to 3.65 | Vitreous to pearly | Pink, rose-red, cherry-red, yellow, yellowish gray, cinnamon-brown, may be banded |
| Chondrodite | 1.60 (mean) | — | Positive | B | 6.5 | 3.1 to 3.2 | Vitreous to Greasy | Yellow, orange, red or brown, rarely colorless |
| Vulcanite | 1.60 to 1.63 | — | — | I | 2 | 1.15 to 1.20 | Metallic | Pale to yellow bronze |
| Vulcanite (hard rubber) | 1.60 to 1.63 | — | — | — | 2 | 1.15 to 1.20 | — | — |
| Grandidierite | 1.602–1.639 | 0.037 | Negative | B | 7.5 | 3 | Vitreous, Pearly | Bluish green |
| Brazilianite | 1.603–1.623 | 0.02 | Positive | B | 5.5 | 2.980 to 2.995 | Vitreous | Yellow, green, colorless |
| Sogdianite | 1.606–1.608 | 0.002 | Negative | U | 6 to 7 | 2.76 to 2.90 | Vitreous | Violet, pale pink |
| Sugilite | 1.607–1.610 | 0.004 | Negative | U | 5.5 to 6.5 | 2.74 | Vitreous | Light brownish-yellow, purple, violet, reddish violet, pale pink, colorless |
| Topaz | 1.610–1.638 | 0.008 to 0.010 | Positive | B | 8 | 3.53 to 3.56 | Vitreous | Colorless (if no impurities), blue, brown, orange, gray, yellow, green, pink and reddish pink |
| Prehnite | 1.61–1.64 | 0.03 | Positive | B | 6 | 2.8 to 2.95, usually 2.88 to 2.94 | Vitreous to pearly | Yellow-green, brown-yellow, gray, white and colorless |
| Persian and Egyptian Turquoise | 1.61–1.65 | 0.04 | Positive | B | 5.5 to 6 | approx. 2.8 | Waxy to subvitreous | Turquoise, Blue, blue-green, green |
| American Turquoise | 1.61–1.65 | 0.04 | Positive | B | 5.5 to 6 | approx. 2.6 | Waxy to subvitreous | Turquoise, Blue, blue-green, green |
| Turquoise | 1.61–1.65 | 0.04 | Positive | B | 5.5 to 6 | 2.6 to 2.85 | Waxy to subvitreous | Turquoise, Blue, blue-green, green |
| Herderite | 1.61 (mean) | 0.03 | Positive | B | 5 | 3 | Vitreous | Colourless, pale yellow, greenish-white |
| Sugilite | 1.610 to 1.607 | 0.003 | Negative | U | 6 to 6.5 | 2.74 | Vitreous | Light brownish-yellow, purple, violet, reddish violet, pale pink, colorless |
| Bakelite | 1.61 to 1.66 | — | — | — | 2.25 | 1.25 to 2.00 , usually 1.26 to 1.30 | — | — |
| Gaspeite | 1.61 to 1.81 | 0.22 | — | — | 4.5 to 5 | 3.7 | Vitreous to dull | Pale green, apple-green, yellowish-green, bright green |
| Bakelite (higher if filled) | 1.61 to 1.66 | — | — | — | 2.5 | 1.25 to 1.30 | — | — |
| Amblygonite | 1.611–1.637 | 0.026 | Positive | B | 6 | 3.01 to 3.03 | Vitreous to pearly[ | Generally white or creamy, but can also be colorless or pale yellow, green, blue, beige, gray, brown or pink. |
| Hemimorphite | 1.612–1.633 | 0.021 | Positive | B | 5 | 3.44 | Vitreous, adamantine, rarely silky | White, blue, greenish |
| Lazulite | 1.615–1.645 | 0.036 | Negative | B | 5.5 | 3.1 | Vitreous | Azure-blue, sky-blue, bluish white, yellow-green, blue-green, rarely green |
| Wollastonite | 1.616–1.631 | 0.015 | Negative | B | 4.5 to 5 | 2.8 to 2.9 | Vitreous or dull to pearly on cleavage surfaces | White, colorless or gray |
| Tourmaline | 1.616–1.634 to 1.630–1.652 | 0.014 to 0.022 | Negative | U | 7 to 7.5 | 3.00 to 3.12 | Vitreous, sometimes resinous | Most commonly black, but can range from colorless, brown, violet, yellow, orange, blue, red, green, pink, or bi-colored, or even tri-colored. |
| Actinolite | 1.620–1.642 | 0.022 | Negative | B | 5 to 5.5 | 3.05 | vitreous to dull | pale to dark green, yellowish green and black. White or grey when in asbestos |
| Smithsonite | 1.62– 1.85 | 0.23 | Negative | U | 5 | 4.30 to 4.35 | Vitreous, may be pearly | White, grey, yellow, green to apple-green, blue, pink, purple, bluish grey, and brown |
| Clinohumite | 1.623–1.651 to 1.632–1.662 | 0.024 to 0.037 | Positive | B | 6 to 6.5 | 3.18 | Vitreous to resinous | Brownish to orange, yellow, red |
| Celestine | 1.625–1.635 | 0.01 | Positive | B | 3.5 | 3.97 to 3.99 | Vitreous, pearly on cleavages | Colorless, white, pale blue, pink, pale green, pale brown, black |
| Datolite | 1.625–1.669 | 0.044 | Negative | B | 5 | 2.9 to 3.00 | Vitreous, rarely subresinous on fracture surface | Colorless or white; may be grayish, yellow, green, red, pink |
| Friedelite | 1.629–1.664 | 0.035 | Negative | U | 4 to 5 | 3.06 to 3.19 | Vitreous (Glassy) | an, brown, "beef steak" |
| Danburite | 1.630–1.636 | 0.006 | Negative | B | 7 | 3 | Vitreous – greasy | Colourless, white, gray, brownish white, straw yellow |
| Apatite | 1.63–1.64 | 0.002 to 0.004 | Negative | U | 5 | 3.17 to 3.23 | Vitreous to subresinous | Transparent to translucent, usually green, less often colorless, yellow, blue to violet, pink, brown. |
| Siderite | 1.633 –1.873 | 0.24 | Negative | U | 3.5 to 4 | 3.83 to 3.88 | Vitreous, may be silky to pearly | Pale yellow to tannish, grey, brown, green, red, black and sometimes nearly colorless |
| Andalusite | 1.634–1.644 to 1.641–1.648 | 0.007 to 0.011 | Negative | B | 7.25 | 3.15 to 3.17 | Vitreous | Pink, violet, yellow, green, white, gray; in thin section, colorless to pink or green |
| Barite / Baryte | 1.636–1.648 | 0.012 | Positive | B | 3 | 4.3 to 4.6 | Vitreous, Pearly | Colorless, white, light shades of blue, yellow, grey, brown |
| Jeremejevite | 1.639–1.648 | 0.009 | Negative | U | 6.5 to 7 | 3.29–3.31 | Vitreous | Colorless, white, yellowish, blue |
| Väyrynenite | 1.639–1.667 | 0.026 | Negative | B | 5 | 3.23 | Vitreous | Light pink to rose-red, salmon pink, pale gray, brown |
| Eosphorite | 1.640–1.645 to 1.668–1.680 | 0.028 to 0.035 | Negative | B | 4.5 | 3.1 | Vitreous, resinous | usually pale brown, golden brown, also medium brown to dark brown; occasionally pink, rose red |
| Jet | 1.64 to 1.68 | — | — | — | 2.5 to 4 | usually 1.20 to 1.30 | Velvety to waxy | Deep black, dark brown |
| Ludlamite | 1.650–1.689 to 1.653–1.693 | 0.04 | Positive | B | 3 to 4 | 3.19 | Vitreous, pearly on cleavage | Apple-green to bright green |
| Malachite | 1.65– 1.90 | 0.25 | Negative | B | 4 | 3.74 to 3.95, usually 3.8 | Adamantine to vitreous; silky if fibrous; dull to earthy if massive | Bright green, dark green, blackish green, commonly banded in masses; green to yellowish green in transmitted light |
| Euclase | 1.652–1.672 | 0.02 | Positive | B | 7.5 | 3.1 | Vitreous | Colorless, white, pale green to deep yellowish green, greenish blue, pale blue to deep blue |
| Peridot | 1.654–1.689 | 0.036 | Positive | B | 6.5 | 3.34 | Vitreous (glassy) | Yellow, to yellow-green, olive-green, to brownish, sometimes a lime-green, to emerald-ish hue |
| Phenakite | 1.654–1.670 | 0.016 | Positive | U | 7.5 to 8 | 2.95 to 2.97 | Vitreous | Colorless, yellow, pink, brown |
| Jadeite | 1.654–1.667, mean 1.66 | 0.013 | Positive | B | 7 | 3.30 to 3.36 | Subvitreous, pearly on cleavages | Apple-green, emerald-green, bluish green, leek-green,greenish white, white, may show green spots, rarely blue or violet; colorless in thin section. Often also banded. |
| Magnesioaxinite | 1.656–1.668 | 0.012 | Negative | B | 6.5 to 7 | 3.18 | Vitreous | Pale Blue to pale Violet; light Brown to light Pink ` |
| Fibrolite | 1.658–1.678 | 0.02 | Positive | B | 6.5 to 7 | 3.25 | Vitreous | Blue, brown, colourless, green, grey |
| Sillimanite | 1.659 - 1.680 | 0.015 to 0.011 | — | — | 6 to 7.5 | 3.25 +/-, 0.02, 0.11 | Vitreous to subadamantine, silky | Colourless or white to grey, also brown, yellow, yellow-green, grey-green, blue-green, blue; colourless in thin section |
| Spodumene | 1.660–1.675 | 0.015 | Positive | B | 7 | 3.17 to 3.19 | Vitreous, pearly on cleavage | Highly variable: white, colorless, gray, pink, lilac, violet, yellow and green, may be bicolored; emerald green - hiddenite; lilac - kunzite; yellow - triphane |
| Serandite | 1.660–1.688 | 0.028 | Positive | B | 4.5 to 5 | 3.32 | Vitreous, greasy | Pink, orange, red, tan, and brown. May oxidize brown or black upon exposure to air. |
| Boracite | 1.66 to 1.67 | — | — | I | 7 | 2.96 | Vitreous - adamantine | Colorless, white, gray, brown, orange, yellow, pale green, dark green, blue-green, or blue; colorless in transmitted light |
| Durangite | 1.662 –1.712 | 0.05 | Negative | B | 5 | 3.97 to 4.07 | Vitreous | Light to dark |
| Enstatite | 1.663–1.673 | 0.01 | Positive | B | 5.5 | 3.26 to 3.28 | Vitreous, pearly on cleavage | White, grey, green, yellow or brown - colorless in thin section. |
| Kornerupine | 1.665–1.678 to 1.668–1.680 | 0.013 | Negative | B | 6.5 | 3.28 to 3.35 | Vitreous | Colorless, white, grey, greenish, bluish, brown, black |
| Lawsonite | 1.665–1.684 | 0.019 | Positive | B | 7 to 8 | 3.09 | Vitreous, greasy | Colorless, white, pale blue to grayish blue |
| Hypersthene | 1.67–1.68 to 1.71–1.73 | 0.010 to 0.020 | Negative | B | 5 to 6 | 3.4 to 3.5 | vitreous to pearly | gray, brown, or green |
| Diopside | 1.67 –1.70 | 0.03 | Positive | B | 5.5 | 3.29 | Vitreous to dull | Commonly light to dark green; may be blue, brown, colorless, white, grey |
| Sinhalite | 1.67 –1.71 | 0.038 | Negative | B | 6.5 | 3.47 to 3.49 | Vitreous | Colourless, yellow-brown, green-brown, brown |
| Parisite | 1.671– 1.772 | 0.01 | Positive | U | 4.5 | 4.33 | Vitreous - greasy | Brown, brownish yellow, gray-yellow, grayish yellow, yellow, waxy yellow, colourless to yellow in transmitted light |
| Legrandite | 1.675 –1.735 | 0.06 | Positive | B | 5 | 3.98 –4.04 | Vitreous | Bright yellow, wax-yellow, colorless |
| Axinite | 1.675–1.685 | 0.01 | Negative | B | 7 | 3.27 to 3.29 | Vitreous | Reddish brown to yellow to colorless. Blue, violet, grey. |
| Dumortierite (massive) | 1.68 (mean) | — | — | B | 7 | 3.26 to 3.41 | Vitreous to dull | Blue, greenish-blue, violet-blue, pale blue, red |
| Triphylite | 1.689–1.695 to 1.694–1.702 | 0.006 to 0.008 | Positive | B | 4 to 5 | 3.42 to 3.52 | Vitreous–subresinous | Green–blue gray, brown–black |
| Rhodizite | 1.69 | — | — | I | 8 | 3.4 | Adamantine, Vitreous | Colourless, white, greyish, yellowish; colourless in transmitted light |
| Willemite | 1.69– 1.72 | 0.028 | Positive | U | 5.5 | 3.89 to 4.18 | Vitreous to resinous | Colorless to white, gray, flesh-red, dark brown, honey-yellow, apple-green, blue |
| Zoisite | 1.692– 1.700 | 0.008 | Positive | B | 6 | 3.35 | Vitreous, pearly on cleavage surfaces | White, gray, greenish brown, greenish gray, pink, blue, purple |
| Idocrase | 1.700–1.712 | 0.005 (mean) | Neg/Pos | U | 6.5 | 3.32 to 3.47 | Vitreous to resinous | Yellow, green, brown; colorless to white, blue, violet, bluish green, pink, red, black, commonly zoned |
| Thulite (zoisite) | 1.700–1.706 | 0.006 | Negative | B | 6 | 3.09 to 3.12 | Vitreous, pearly on cleavage surfaces | Pink |
| Serendibite | 1.700–1.743 | 0.006 | Positive | B | 6.5 to 7 | 3.42 to 3.52 | Vitreous | pale yellow, blue-green, greyish blue, black |
| Chlorastrolite | 1.70 (mean) | — | — | B | 5 to 6 | 3.1 to 3.5 | — | — |
| Smaragdite | 1.70 approx. | — | — | — | 5 to 5.5 | 3.25 | Vitreous | Emerald green |
| Diaspore | 1.702–1.750 | 0.048 | Positive | B | 6.5 to 7 | 3.30 to 3.35 | Adamantine, vitreous, pearly on cleavage faces | White, pale gray, colorless, greenish gray, brown, pale yellow, pink, purple; may exhibit color change |
| Arandisite | 1.704 approx. | — | — | — | 5 | 4 | — | Bright green |
| Sapphirine | 1.705–1.711 | 0.006 | Neg/Pos | B | 7.5 | 3.40 to 3.58 | Vitreous | Light to dark blue or green, white, gray, pale red, yellow |
| Adamite | 1.710–1.759 to 1.742–1.773 | 0.031 to 0.050 | Positive | B | 3.5 | 4.30 to 4.68 | Vitreous | Pale yellow, honey-yellow, brownish yellow, reddish; rarely white, colorless, blue, pale green to green, may be zoned; |
| Spinel | 1.714 to 1.736 | — | — | I | 8 | 3.58 to 3.64 | Vitreous | Various; red, pink, blue, lavender/violet, dark green, brown, black, clear |
| Kyanite directional | 1.715–1.732 | 0.017 | Negative | B | 5 to 7 | 3.65 to 3.68 | Vitreous to pearly | Blue, white, rarely green, gray, yellow, pink, orange, and black, can be zoned |
| Taaffeite | 1.718–1.722 | 0.004 | Negative | U | 8 | 3.60 to 3.61 | Vitreous | Colorless, greyish violet, violet red, red, greenish, light green, pink violet, mauve |
| Massive grossular garnet | 1.72 | — | — | I | 7.25 | 3.36 to 3.55 | greasy to vitreous | light to dark green, light to dark yellow to reddish brown, occasionally translucent to opaque pink. It is also but rarely found in colorless form[1] |
| Hydrogrossular | 1.72 | — | — | — | 7 | 3.47 to 0.08 - 0.32 | vitreous | green to bluish green, pink, white, gray |
| Clinozoisite | 1.72–1.73 | 0.01 | Positive | B | 6 to 6.5 | 3.37 | Vitreous | Colorless, green, gray, light green, yellow green |
| Bromellite | 1.720–1.735 | 0.015 | Positive | U | 9 | 3.00 to 3.02 | Vitreous | White, colorless |
| Hodgkinsonite | 1.720–1.746 | 0.026 | Negative | B | 4.5 to 5 | 3.95 | Vitreous (Glassy) | Light pink, Orange, Reddish brown. |
| Synthetic spinel | 1.724 to 1.729 | — | — | I | 8 | 3.61 to 3.65 | Subadamantine To Vitreous | red, yellow, brown, light to dark green, grayish green, yellowish green, pale pink to pink, light to dark blue, greenish blue, violet, mauve, orange, colorless |
| Azurite | 1.73 –1.84 | 0.11 | Positive | B | 3.5 to 4 | 3.77 to 3.89 | Vitreous | Azure-blue, Berlin blue, very dark to pale blue; pale blue in transmitted light |
| Pyrope garne | 1.73 to 1.75 | — | — | I | 7.25 | 3.65 to 3.70 | greasy to vitreous | Red. Some varieties are very dark, almost black, while others can take tones of purple. Some chromium-rich pyropes are thermochromic, becoming green when heated |
| Chambersite | 1.732–1.744 | 0.01 | Positive | B | 7 | 3.49 | Vitreous | Colorless to deep purple |
| Epidote | 1.736–1.770 | 0.034 | Negative | B | 6.5 | 3.25 to 3.50, usually 3.4 | Vitreous to resinous | Pistachio-green, yellow-green, greenish black |
| Pyroxmangite | 1.736–1.753 | 0.017 | Positive | B | 5 to 6 | 3.76 (mean) | vitreous, pearly | pink, red, brown |
| Musgravite | 1.739 to 1.735 | 0.014 to 0.016 | — | U | 8 to 8.5 | 3.6 to 3.68 | Vitreous | Grey green to green |
| Periclase | 1.737 | — | — | I | 5 | 3.55 to 3.60 | Vitreous | Colorless, grayish white, yellow, brownish yellow, green, black |
| Staurolite | 1.739–1.750 to 1.747–1.762 | 0.011 to 0.015 | Positive | B | 7 to 7.5 | 3.65 to 3.78 | Subvitreous to resinous | Dark reddish brown to blackish brown, yellowish brown, rarely blue; pale golden yellow in thin section |
| Gahnospinel | 1.74 (mean) | — | — | I | 8 | 3.75 (mean) | Vitreous | Green, Blue Dark In Tone, Very Dark Green, Brown To Black |
| Scorodite | 1.74 to 1.81 | — | Neg/Pos | B | 4 | 3.22 | Sub-Adamantine, Vitreous, Resinous | Green, blue-green, grey, grayish-green, blue, yellow-brown, nearly colorless, violet |
| Hessonite garnet | 1.742 to 1.748 | — | I | 7.25 | 3.65 | Vitreous | Brown-red |
|
| Chrysoberyl | 1.75–1.76 | — | Positive | B | 8.5 | 3.71 to 3.72 | Vitreous | Various shades of green, yellow, brownish to greenish black, may be raspberry-red under incandescent light when chromian; colorless, pale shades of yellow, green, or red in transmitted light |
| Corundum | 1.760-1.768 to 1.77-1.779 | 0.008 to 0.010 | Negative | U | 9 | 3.90 to 4.00 | Adamantine to vitreous | Colorless, gray, brown; pink to red, orange, yellow, green, blue, violet; may be color zoned, asteriated mainly grey and brown |
| Almandine/ pyrope garnet | 1.75 to 1.78 | — to 0.010 | — | I | 7.5 | 3.80 to 3.95 | Vitreous | Red |
| Pyrope/almandine series garnet | 1.75 to 1.78 | — | — | I | 7.5 | 3.70 to 3.95 | Greasy to vitreous | Red. Some varieties are very dark, almost black, while others can take tones of purple. Some chromium-rich pyropes are thermochromic, becoming green when heated |
| Planchéite | 1.752 –1.815 | — | — | — | 6 | 3.8 | Silky | Blue, greenish blue |
| Benitoite | 1.757 –1.804 | 0.047 | Positive | U | 6.5 | 3.65 to 3.68 | Vitreous | Blue, colorless |
| Rhodolite | 1.76 | — | — | — | 7 to 7.5 | 3.84 to 0.001 +/- | Greasy to vitreous | Light to dark purplish red through reddish purple |
| Spinel (Ceylonite) | 1.77–1.80 | — | — | I | 8 | 3.63 to 3.90 | Vitreous | Various; red to blue to mauve, dark green, brown, black |
| Zircon (low type) | 1.78 to 1.81 | — | — | I | 6 | 3.90 to 4.10 | Greasy to adamantine. Radioactive Zircon has a pitchy luster. | The most common color is dark brown. Also black, gray, light brown, brownish-red, orange, pink, yellow, light blue, light green, light purple white, and colorless. Sometimes multicolored black and dark red, or multicolored with lighter and darker streaks. |
| reddish orange to red, slightly purplish red to reddish purple and usually dark in tone | 1.78 to 1.81 | — | — | I | 7.5 | 3.95 to 4.20 | greasy to vitreous | reddish orange to red, slightly purplish red to reddish purple and usually dark in tone |
| Painite | 1.787 –1.816 | 0.029 | Negative | U | 7.5 | 4.01 | Vitreous | Red, brownish, orange-red |
| Spessartine garnet | 1.79 to 1.81 | — | — | I | 7.25 | 4.12 to 4.20 | Vitreous | Yellow through red |
| Monazite | 1.795– 1.845 | 0.05 | Positive | B | 6 | 5.2 | Resinous, vitreous to adamantine | Reddish brown, brown, pale yellow, pink, green, gray |
| Gahnite | 1.8 | — | — | I | 7.5 to 8 | 4.4 | Vitreous | Dark green, bluish green, blue to indigo, yellow to brown |
| Cerussite | 1.804– 2.078 | 0.274 | Negative | B | 3 to 3.5 | 6.46 to 6.57 | Adamantine, vitreous, resinous | Colorless, white, gray, blue, or green |
| Yttrium aluminium garnet | 1.83 | — | — | — | 8 to 8.5 | 4.57 to 4.60 | Adamantine, vitreous, resinous | Dark green, bluish green, blue to indigo, yellow to brown |
| Uvarovite garnet | 1.87 | — | — | I | 7.5 | 3.77 | Vitreous | Green, emerald-green, green-black |
| Anglesite | 1.877–1.894 | 0.017 | Positive | B | 2.75 to 3 | 6.30 to 6.39 | Adamantine crystals, dull when massive earthy | Colorless to white, commonly tinted gray; orange, yellow, green, blue, rarely violet |
| Sphene | 1.88– 1.99 | 0.105 | Positive | B | 5.5 | 3.52 to 3.54 | Adamantine | Yellow, brown, green, reddish |
| Demantoid garnet | 1.89 | — | — | I | 6.5 | 3.82 to 3.85 | Vitreous, diamond-like, adamantine | Yellow-green, green to emerald green |
| Scheelite | 1.918–1.934 | 0.016 | Positive | U | 4.5 to 5 | 5.9 to 6.1 | Vitreous to adamantine | Colorless, white, gray, brown, pale yellow, yellow-orange, pale shades of orange, red, green; may be compositionally color zoned |
| Yttrium oxide | 1.92 | — | — | I | 7.5 to 8 | 4.84 | vitreous to subadamantine | usually colorless, but may be pink, red, orange, yellow, green, blue, purple |
| ‘Yttralox’ | 1.92 | — | — | — | 6.5 | 5.3 | — | — |
| Gadolinium gallium garnet | 1.92–2.03 | — | — | I | 6.5 | 7.05 | vitreous to subadamantine | transparent, colorless to light brown or yellow. May also be orange or blue |
| Zircon (high type) | 1.925–1.984 | 0.059 | Positive | U | 7 to 7.5 | 4.67 to 4.70 | Vitreous to adamantine; greasy when metamict. | Reddish brown, yellow, green, blue, gray, colorless; in thin section, colorless to pale brown |
| Rhombic yttrium aluminate | 1.938–1.955 | 0.017 | ? | B | 8 | 5.35 | — | — |
| Bayldonite | 1.95–1.99 | 0.02 | Positive | B | 4.5 | 4.35 | Resinous | Green, apple-green |
| Powellite | 1.974–1.984 | 0.01 | Positive | U | 3.5 | 4.34 | Adamantine | Straw-yellow, greenish yellow, yellow-brown, brown, colorless, may show blue to black zones |
| Cassiterite | 2.003–2.101 | 0.098 | Positive | U | 6.5 | 6.8 to 7 | Adamantine to adamantine metallic, splendent; may be greasy on fractures | Black, brownish black, reddish brown, red, yellow, gray, white; rarely colorless |
| Zincite | 2.013–2.029 | 0.016 | Positive | U | 4 to 4.5 | 5.66 | Subadamantine to resinous | Yellow-orange to deep red, rarely yellow, green, colorless |
| Boléite | 2.030–2.050 | 0.02 | Negative | U | 3.5 | 5.05 | — | — |
| Simpsonite | 2.06 | 0.1 | — | U | 7 | 6 | Vitreous to adamantine | White to cream, yellow to yellow-brown when altered |
| Euxenite | 2.06 to 2.26 | — | — | — | 6.5 | 4.7 to 5.0 | Brilliant submetallic, waxy to resinous on fractures | Black, brownish black,greenish black |
| Cubic zirconia | 2.09 to 2.18 | — | — | I | 8 to 8.5 | 5.98 to 6.06 | — | — |
| Chromite | 2.1 | — | — | I | 5.5 | 4.1 to 4.9 | Submetallic | Black to brownish black; brown to brownish black on thin edges in transmitted light |
| Phosgenite | 2.114–2.140 | 0.026 | Positive | U | 3 | 6.2 | Adamantine | Pale yellow to yellowish brown, pale brown, smoky brown, smoky violet; colorless, pale rose, gray, yellowish gray, pale green |
| Mimetite | 2.120–2.135 | 0.015 | Negative | U | 3.5 | 7.0 to 7.25 | Resinous, subadamantine | Pale to bright yellow, yellowish brown, yellow-orange, white, may be colorless |
| Manganot- antalite | 2.14–2.22 to 2.19–2.34 | 0.008 to 0.015 | — | B | 5.5–6 | 7.73–7.97 | Vitreous | Scarlet-red to dark red. |
| Samarskite | 2.21 | — | — | B | 5 to 6 | 4.1 to 6.2 | Vitreous - resinous | Black, may have a brownish tint, brown to yellowish brown due to alteration; light to dark brown in transmitted light |
| Lithium niobate | 2.21–2.30 | 0.9 | — | — | 6 | 4.64 | — | — |
| Wulfenite | 2.304–2.402 | 0.098 | Negative | U | 2.75 to 3 | 6.7 to 7 | Adamantine, resinous | Orange-yellow, yellow, honey-yellow, reddish-orange, rarely colorless, grey, brown, olive-green and even black |
| Crocoite | 2.31–2.66 | 0.35 | Positive | B | 2.5 to 3 | 5.9 to 6.1 | Adamantine | Orange, red, yellow |
| Sphalerite | 2.369 | — | — | I | 3.5 to 4 | 3.9 to 4.2 | Adamantine, resinous, greasy | Brown, yellow, red, green, black. |
| Zinc blende | 2.368–2.371 | — | — | I | 3.5 to 4 | 4.08 to 4.10 | — | — |
| Stibiotantalite | 2.39–2.46 | 0.07 | Positive | B | 5.5 to 6 | 7.46 | Adamantine, Resinous | Yellow to dark brown, reddish or greenish brown |
| Calcium titanate | 2.4 | — | — | B | 6 | 4.05 | — | — |
| Strontium titanate | 2.41 | — | — | I | 6 | 5.13 | Adamantine | Usually colorless. Rare earth or transition metals can be added to produce red, orange, yellow, brown, blue. |
| Diamond | 2.42 | — | — | I | 10 | 3.52 | Adamantine | Typically yellow, brown, or gray to colorless. Less often blue, green, black, translucent white, pink, violet, orange, purple, and red. |
| Anatase | 2.493–2.554 | 0.061 | Negative | U | 5.5 to 6 | 3.82 to 3.95 | Adamantine to splendent, metallic | Black, reddish to yellowish brown, dark blue, gray |
| Greenockite | 2.505–2.529 | 0.024 | Positive | U | 3.5 | 4.83 to 4.90 | Adamantine to resinous | Honey yellow, citron yellow, orange yellow |
| Brookite | 2.583–2.705 | 0.122 | Positive | B | 5.5 to 6 | 3.87 to 4.08 | Submetallic | Deep red, reddish brown, yellowish brown, brown, or black |
| Rutile (natural and synthetic) | 2.62–2.90 | 0.287 | Positive | B | 6 to 6.5 | 4.2 | Adamantine to submetallic | Reddish brown, red, pale yellow, pale blue, violet, rarely grass-green; black if high in Nb–Ta |
| Rutile | 2.62–2.90 | 0.287 | Positive | U | 6 to 6.5 | 4.2 | Adamantine to submetallic | Reddish brown, red, pale yellow, pale blue, violet, rarely grass-green; black if high in Nb–Ta |
| Carborundum | 2.65–2.69 | 0.043 | Positive | U | 9.25 | 3.17 | — | blue-black colour, rainbow sheen |
| Proustite | 2.7 to 3.0 | 0.3 | Negative | U | 2 to 2.5 | 5.57 to 5.64 | Adamantine | Scarlet-vermilion |
| Cuprite | 2.85 | — | — | I | 3.5 to 4 | 5.85 to 6.15 | Adamantine, sub-metallic, earthy | Dark red to conchineal red, sometimes almost black |
| Hematite | 2.94–3.22 | — | — | U | 6.5 | 4.95 to 5.16 | Metallic to splendent | Metallic gray, dull to bright red |
| Marble | — | — | — | — | — | 2.5 to 2.6 | — | — |
| Nevada wonderstone | — | — | — | — | 6 to 6.5 | approx. 2.5 | — | — |
| Unakite | — | — | — | — | 6 to 7 | 2.85 to 3.20 | — | |
| Magnetop- lumbite | — | — | — | — | 6 | 5.5 to 5.7 | Sub-Metallic | Grey-black |
| Blue pearl | — | — | — | — | — | 2.40 to 2.65 | — | — |
| Porcelain | — | — | — | — | 4 approx. | 2.3 | — | — |
| Bornite | — | — | — | — | 3 | 4.9 to 5.4 | Metallic if fresh, iridescent tarnish | Copper red, bronze brown, purple |
| Conch pearl | — | — | — | — | 3.5 to 4 | 2.84 to 2.89 | — | — |
| Fine pearl | — | — | — | — | — | 2.69 to 2.73 | — | — |
| Microlite | — | — | — | I | 5.5 | 5.5 | Vitreous - Resinous | Yellowish brown, Reddish brown, Greenish brown, Green, Gray. |
| Chalcopyrite | — | — | — | — | 3.5 to 4 | 4.2 approx. | Metallic | Brass yellow, may have iridescent purplish tarnish. |
| Elephant Ivory | 1.54 | — | — | — | 2.5 to 2.75 | 1.70 to 2.00 | — | — |
| Black clam | — | — | — | — | — | 2.20 to 2.66 | — | — |
| Domeykite | — | — | — | — | 3.5 | 7.2 to 7.9 | Metallic | Tin-white to steel-gray |
| Pinite | — | — | — | — | 2.5 | 2.60 to 2.85 | — | — |
| Mollusc shell | — | — | — | — | 3.5 to 4 | approx. 2.8 | — | — |
| Pentlandite | — | — | — | — | 3.5 to 4 | 5 | metallic | Yellowish bronze |
| Psilomelane | — | — | — | — | 7 | 4.35 approx. | Sub-Metallic, Dull | black with gray pyrolusite bands |
| Breithauptite | — | — | — | — | 4.5 to 5 | 7.54 | Metallic | Pale copper-red, may be with violet tint |
| Pyrite | — | — | — | — | 6.5 | 4.95 to 5.10 | Metallic | Brass yellow - often tarnished to dull brass |
| Marcasite | — | — | — | — | 6 to 6.5 | 4.85 to 4.90 | Metallic | Tin-white on fresh surface, pale bronze-yellow, darkening on exposure, iridescent tarnish |
| Hippopotamus walrus and narwhal | — | — | — | — | — | 1.85 to 1.98 | — | — |
| Cultured pearl | — | — | — | — | — | 2.70 to 2.78 | — | — |
| Niccolite | — | — | — | U | 5 to 5.5 | 7.33 to 7.67 | metallic | Pale copper red with blackish tarnish. white with strong yellowish pink hue on polished section strongly anisotropic |
| Calcium | — | — | — | B | 6 | 4.05 | — | — |
| Australian pearl | — | — | — | — | — | 2.67 to 2.78 | — | — |
| Cobaltite | — | — | — | I | 5.5 | 6.0 to 6.3 | Metallic | Reddish silver white, violet steel gray to black |
| Algodonite | — | — | — | — | 3.5 | 8.38 | Metallic | Gray, silver white, steel gray, tarnishes dull bronze |
| Kakortokite | — | — | — | — | Varies | 2.7 to 2.8 | — | — |
| Barium titanate | 2.40 | — | — | — | 6 to 6.5 | 5.9 | — | — |
gemstone identification chart
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