MALAKE · GEMOLOGY REFERENCE
IGI Gem Identification Chartاستاندارد بینالمللی شناسایی گوهر
IGI SCHOOL OF GEMOLOGY
GEM IDENTIFICATION CHART
مواد با شکست نور بالا — از Hematite تا Apatite
برای دیدن همه ستونها، جدول را به چپ و راست بکشید
| GEM MATERIAL | COLORS | TRANSPARENCY | VISUAL CHARACTERISTICS | REFRACTIVE INDEX | Op. Char., Crystal Sys. | PLEOCHROISM | VARIETIES | SPECTRUM | UV FLUOR. | SPECIFIC GRAVITY | HARDNESS | COMMENTS | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| RI (norm) | Range | Biref. | ||||||||||||
| Hematite | Gr,Bl | Opaque | Metallic luster | 2.940-3.220 | -0.07 | 0.28 | AGG, Hexagonal | — | — | — | — | 5.20; +0.08, -0.25 | 5½ to 6½ | Streak test- reddish brown |
| Diamond | All colors | Tp to Opaque | Adamantine luster | 2.417 | — | — | SR, Cubic | — | — | 415.5 in cape series | LW-in to str, SW-in | 3.52 ±0.01 | 10 | High thermal conductivity |
| CZ | All colors | Tp | Strong dispersion | 2.15 | 0.03 | — | SR, Cubic | — | — | — | LW&SW-in to mod | 5.8 ±0.02 | 8½ | — |
| Sphene | O,Y,G,Br | Tp | Very strong doubling | 1.900-2.034 | +-0.020 | 0.1,-0.135 | DR,B+,Monoclinic | Tri, mod to strong | — | 580 doublet | LW&SW-inert | 3.52 ±0.02 | 5 to 5½ | Abraded facet edges, doubling |
| Zircon | C,P,R,O,Y,G,B,Br | Tp to S-Tp | C(rare),Subadamantine luster | 1.925-1.984 | 0.04,-0.145 | 0.000 to 0.059 | DR,U+,Tetragonal | Di, weak to strong | — | 653.5 line | LW&SW-in to mod | 4.7; 0.03, -0.80 | 6 to 7½ | Abraded facet edges, doubling |
| Andradite | Y,G,Br,Bl | Tp to O | C(rare) | 1.888 | 0.007,-0.033 | — | SR, Cubic | — | Demantoid, Melanite | 440.0 line | LW&SW-inert | 3.84 ±0.03 | 6½ to 7 | Demantoid-Horse tail like inclusions |
| Spessartite | R,O,Br | Tp | Color contains some orange | 1.81 | 0.004,-0.02 | — | SR, Cubic | — | — | 412, 430 bands key | LW&SW-inert | 4.15; 0.05, -0.03 | 7 to 7½ | — |
| Almandite | P,R,Br | Tp to S-Tl | A,often dark in tone | 1.79 | ±0.030 | — | SR, Cubic | — | — | 505, 525, 575 bands | LW&SW-inert | 4.05; 0.25, -0.12 | 7 to 7½ | Needle-like incls intersect at 70° and 110° |
| Corundum | All colors | Tp to O | A,CC,C(rare) | 1.762-1.770 | 0.009,-0.005 | 0.008,-0.010 | DR,U-,Trigonal | Di, weak to strong | Ruby, Sapphire | varies with color | LW&SW-in to strong | 4.00; 0.10, -0.05 | 9 | silk, rutile needles Intersecting at 60° and 120° |
| Syn. Corundum (FI) | All colors | Tp to Opaque | A,CC,C(rare) | 1.762-1.770 | 0.005,-0.003 | 0.008 | DR,U-,Trigonal | Di, weak to strong | Ruby, Sapphire | varies with color | LW&SW-in to strong | 4.00; ±0.03 | 9 | gas bubbles, curved striations |
| Syn. Corundum (F) | All colors | Tp | — | 1.762-1.770 | — | 0.008 | DR,U-,Trigonal | Di, mod to strong | Ruby, Sapphire | varies with color | LW&SW-in to strong | 4.00; ±0.03 | 9 | flux, flux fingerprint, metallic inclusions, wispy veil |
| Rhodolite | P,R | Tp | Purple to purplish red color | 1.76 | 0.010,-0.020 | — | SR, Cubic | — | — | 505, 525, 575 bands | LW&SW-inert | 3.84; ±0.01 | 7 to 7½ | — |
| Chrysoberyl | P,R,Y,G,B,Br | Tp to O | C,CC | 1.746-1.755 | 0.004,-0.006 | 0.008,-0.010 | DR,B+,Orthorhombic | Tri, weak to strong | Alexandrite, cat'seye | varies with color | LW-in to weak | 3.73; ±0.02 | 8½ | Syn Alexandrite has slightly lower RI and stronger fluo than nat. |
| Pyrope | R | Tp | Often very dark in tone | 1.746 | 0.010,-0.026 | — | SR, Cubic | — | — | 505, 560 broad bands | LW&SW-inert | 3.78; 0.09, -0.16 | 7 to 7½ | — |
| Grossularite | O,Y,G,Br | Tp to S-Tp | — | 1.74 | 0.020,-0.010 | — | SR, Cubic | — | Hessonite, Tsavorite | varies with color | LW&SW-inert to mod | 3.61; 0.12, -0.04 | 7 to 7½ | Hessonite-Heat wave effect |
| Azurite | B | Tl-O | — | 1.730-1.836 | +-0.010 | 0.106 | AGG, Monoclinic | Tri, strong to mod | — | — | — | 3.80; 0.09, -0.50 | 3½ to 4 | generally associated with malachite, intergrowth called azurmalachite |
| Hydrogrossular | G,Br | Tl-O | — | 1.72 | 0.010,-0.030 | — | AGG, Cubic | — | — | varies with color | LW&SW-inert | 3.47; 0.08, -0.32 | 7 | — |
| Syn. Spinel | All colors | Tp-O | CC,Colorless,light Y,G,B,dark B → common | 1.728 | 0.012,-0.008 | — | SR, Cubic | — | — | varies with color | LW&SW-in to strong | 3.64; 0.02, -0.12 | 8 | Syn blue spinel SW-Chalky blue fluo |
| Spinel | All colors | Tp-O | CC(rare),colors often low in → saturation | 1.718 | 0.017,-0.008 | — | SR, Cubic | — | — | varies with color | LW-in to str, SW-in | 3.60; 0.10, -0.03 | 8 | Octahedral crystals as inclusions |
| Kyanite | C,G,B | Tp | C(rare) | 1.716-1.731 | +-0.004 | 0.012-0.017 | DR,B-,Triclinic | Tri, mod | cat's eye | 435, 445 bands | LW-in to weak | 3.68; 0.01, -0.12 | 4 to 7½ | Directional hardness |
| Zoisite | R,G,B,V,Br,Gr | Tp-O | C(rare),very strong pleochroism | 1.691-1.700 | +-0.005 | 0.008-0.013 | DR,B+,Orthorhombic | Tri, strong | Tanzanite | varies with color | LW&SW-inert | 3.35; 0.10, -0.25 | 6 to 7 | — |
| Diopside | G,B,V,Bl | Tp-O | A,C | 1.675-1.701 | 0.029,-0.010 | 0.024-0.030 | DR,B+,Monoclinic | Tri, weak to mod | cat's eye, star | 505 line common | — | 3.29; 0.11, -0.07 | 5½ to 6 | cat's eye commonly green, star-4 rayed star commonly black |
| Enstatite | G,Br | Tp-Tl | C,A(rare),often dark in tone | 1.663-1.673 | +-0.010 | 0.008-0.011 | DR,B+,Orthorhombic | Tri, weak to strong | — | 505, 550 lines | LW&SW-inert | 3.25; 0.15, -0.02 | 5 to 6 | — |
| Spodumene | P,R,Y,G,B,V,Gr | Tp | — | 1.660-1.676 | +-0.005 | 0.014-0.016 | DR,B+,Monoclinic | Tri, weak to strong | Kunzite, Hiddenite | varies with color | LW-in to str, SW-weak | 3.18; ±0.03 | 6½ to 7 | Kunzite-pale pink, Hiddenite-pale green |
| Sillimanite | G,B,Br,W,Gr | Tp-O | C | 1.654-1.670 | 0.004,-0.006 | 0.011-0.015 | DR,B+,Orthorhombic | Tri, mod to strong | — | — | — | 3.25; 0.2, -0.11 | 6 to 7½ | generally-fibrous, also known as fibrolite |
| Jadeite | All colors | S-Tp to O | often greasy to waxy luster | 1.660spot | +-0.008 | — | AGG, Monoclinic | — | — | 437 line | LW-in to strong | 3.34; 0.06, -0.09 | 6 to 7½ | — |
| Malachite | G | O | Banded with 2 or more tones of G | 1.655-1.909 | — | 0.254 | AGG, Monoclinic | — | — | — | LW&SW-inert | 3.95; 0.15, -0.70 | 3½ to 4 | curved or angular banding |
| Peridot | Y,G,Br | Tp | — | 1.654-1.690 | +-0.020 | 0.035-0.038 | DR,B+,Orthorhombic | Tri,weak to mod | — | 457,477,497 lines | LW&SW-inert | 3.34; 0.14, -0.07 | 6½ to 7 | lily pad like inclusions |
| Andalusite | R,O,Y,G,Br,W,Gr,Bl | Tp-O | very strong pleochroism | 1.634-1.643 | +-0.005 | 0.007-0.013 | DR,B-Orthorhombic | Tri,strong | — | varies with color | LW-in, SW-in to mod | 3.17; ±0.04 | 7 to 7½ | var:chiastolite, Ti-O, with dark cross like pattern on Br material |
| Tourmaline | All colors | Tp-O | C,CC(rare),strong dichroism | 1.624-1.644 | 0.011,-0.009 | 0.018-0.020 | DR,U-,Trigonal | Di,weak to strong | — | varies with color | LW&SW-in to weak | 3.06; 0.20, -0.06 | 7 to 7½ | trichite inclusions, confused with andalusite, topaz and apatite |
| Apatite | C,P,R,Y,G,B,V,Br | Tp-Tl | C | 1.634-1.638 | 0.012,-0.006 | 0.002-0.008 | DR,U-,Hexagonal | Di, weak to strong | — | varies with color | LW&SW-in to weak | 3.18; ±0.05 | 5 | 580 doublet in C, Y, ;confused with andalusite, tourmaline, topaz |
COLORS
TRANSPARENCY
PHENOMENA
منبع: IGI School of Gemology · Gem Identification Chart
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