Caractère Optique des Gemmes — Tableau du Polariscope
Caractère optique de 132 espèces — 34 monoréfringentes, 75 biréfringentes et 23 agrégats — avec indication de l'ADR et biréfringence. Entre polariseurs croisés, une pierre SR reste sombre, une pierre DR s'éclaire quatre fois par tour et un agrégat reste clair. Groupées SR d'abord, puis uniaxes, biaxes et agrégats.
Les noms des gemmes figurent sous leur forme commerciale internationale (anglais) et renvoient à la fiche détaillée de chaque espèce (en anglais).
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Essayer Loupewise Gratuitement →| Gemme | Caractère Optique | ADR | Biréfringence | Plage IR |
|---|---|---|---|---|
| Almandine Garnet | SR | ✓ | — | 1.770–1.830 |
| Amber | SR | ✓ | — | 1.539–1.545 |
| Black Opal | SR | — | — | 1.440–1.460 |
| Black Spinel | SR | ✓ | — | 1.712–1.730 |
| Blue Diamond | SR | ✓ | — | 2.417 |
| Brown Diamond | SR | ✓ | — | 2.417 |
| Color-Change Garnet | SR | ✓ | — | 1.740–1.765 |
| Cubic Zirconia | SR | ✓ | — | 2.150–2.180 |
| Cuprite | SR | — | — | 2.849 |
| Demantoid Garnet | SR | ✓ | — | 1.880–1.895 |
| Diamond | SR | ✓ | — | 2.417 |
| Fire Opal | SR | — | — | 1.370–1.470 |
| Fluorite | SR | — | — | 1.432–1.436 |
| Grossular Garnet | SR | ✓ | — | 1.734–1.759 |
| Hackmanite | SR | — | — | 1.483–1.487 |
| Hauyne | SR | — | — | 1.494–1.509 |
| Hessonite Garnet | SR | ✓ | — | 1.730–1.760 |
| Jet | SR | — | — | 1.640–1.680 |
| Low-Type Zircon | SR | — | — | 1.780–1.815 |
| Malaya / Umbalite Garnet | SR | ✓ | — | 1.730–1.780 |
| Moldavite | SR | — | — | 1.480–1.510 |
| Obsidian | SR | ✓ | — | 1.480–1.510 |
| Opal | SR | — | — | 1.370–1.470 |
| Pink Diamond | SR | ✓ | — | 2.417 |
| Pyrope Garnet | SR | ✓ | — | 1.730–1.760 |
| Rhodolite Garnet | SR | ✓ | — | 1.740–1.770 |
| Spessartite Garnet | SR | ✓ | — | 1.790–1.815 |
| Sphalerite | SR | — | — | 2.369–2.371 |
| Spinel | SR | ✓ | — | 1.712–1.736 |
| Star Garnet | SR | ✓ | — | 1.770–1.830 |
| Synthetic Spinel | SR | ✓ | — | 1.725–1.728 |
| Tsavorite Garnet | SR | ✓ | — | 1.730–1.760 |
| YAG | SR | — | — | 1.833 |
| Yellow Diamond | SR | ✓ | — | 2.417 |
| Amethyst | Uniaxial (+) | — | 0.009 | 1.544–1.553 |
| Ametrine | Uniaxial (+) | — | 0.009 | 1.544–1.553 |
| Benitoite | Uniaxial (+) | — | 0.047 | 1.757–1.804 |
| Cassiterite | Uniaxial (+) | — | 0.096 | 1.997–2.093 |
| Cinnabar | Uniaxial (+) | — | 0.351 | 2.905–3.256 |
| Citrine | Uniaxial (+) | — | 0.009 | 1.544–1.553 |
| Moissanite | Uniaxial (+) | — | 0.043 | 2.648–2.691 |
| Phenakite | Uniaxial (+) | — | 0.016 | 1.654–1.670 |
| Prasiolite | Uniaxial (+) | — | 0.009 | 1.544–1.553 |
| Rock Crystal | Uniaxial (+) | — | 0.009 | 1.544–1.553 |
| Rose Quartz | Uniaxial (+) | — | 0.009 | 1.544–1.553 |
| Smoky Quartz | Uniaxial (+) | — | 0.009 | 1.544–1.553 |
| Zircon | Uniaxial (+) | — | 0.059 | 1.925–1.984 |
| Apatite | Uniaxial (−) | — | 0.006 | 1.628–1.649 |
| Aquamarine | Uniaxial (−) | — | 0.006 | 1.577–1.583 |
| Calcite | Uniaxial (−) | — | 0.172 | 1.486–1.658 |
| Chrome Tourmaline | Uniaxial (−) | — | 0.018 | 1.624–1.660 |
| Color-Change Sapphire | Uniaxial (−) | — | 0.008 | 1.762–1.770 |
| Emerald | Uniaxial (−) | — | 0.006 | 1.565–1.602 |
| Goshenite | Uniaxial (−) | — | 0.006 | 1.577–1.583 |
| Green Tourmaline | Uniaxial (−) | — | 0.018 | 1.616–1.650 |
| Heliodor | Uniaxial (−) | — | 0.006 | 1.568–1.580 |
| Hematite | Uniaxial (−) | — | 0.280 | 2.940–3.220 |
| Indicolite | Uniaxial (−) | — | 0.018 | 1.624–1.644 |
| Morganite | Uniaxial (−) | — | 0.008 | 1.572–1.600 |
| Padparadscha Sapphire | Uniaxial (−) | — | 0.008 | 1.762–1.770 |
| Paraiba Tourmaline | Uniaxial (−) | — | 0.018 | 1.624–1.644 |
| Pink Sapphire | Uniaxial (−) | — | 0.008 | 1.762–1.770 |
| Red Beryl | Uniaxial (−) | — | 0.007 | 1.564–1.574 |
| Rhodochrosite | Uniaxial (−) | — | 0.220 | 1.600–1.820 |
| Rubellite | Uniaxial (−) | — | 0.018 | 1.624–1.644 |
| Ruby | Uniaxial (−) | — | 0.008 | 1.762–1.770 |
| Sapphire | Uniaxial (−) | — | 0.008 | 1.762–1.770 |
| Scapolite | Uniaxial (−) | — | 0.020 | 1.540–1.572 |
| Star Ruby | Uniaxial (−) | — | 0.008 | 1.762–1.770 |
| Star Sapphire | Uniaxial (−) | — | 0.008 | 1.762–1.770 |
| Sugilite | Uniaxial (−) | — | 0.002 | 1.607–1.610 |
| Synthetic Color-Change Corundum | Uniaxial (−) | — | 0.008 | 1.762–1.770 |
| Taaffeite | Uniaxial (−) | — | 0.004 | 1.719–1.723 |
| Tourmaline | Uniaxial (−) | — | 0.020 | 1.624–1.644 |
| Watermelon Tourmaline | Uniaxial (−) | — | 0.018 | 1.616–1.650 |
| White Sapphire | Uniaxial (−) | — | 0.008 | 1.762–1.770 |
| Yellow Sapphire | Uniaxial (−) | — | 0.008 | 1.762–1.770 |
| Alexandrite | Biaxial (+) | — | 0.009 | 1.746–1.755 |
| Cat's Eye Chrysoberyl | Biaxial (+) | — | 0.009 | 1.746–1.755 |
| Chrome Diopside | Biaxial (+) | — | 0.030 | 1.664–1.730 |
| Chrysoberyl | Biaxial (+) | — | 0.009 | 1.746–1.755 |
| Clinohumite | Biaxial (+) | — | 0.028 | 1.625–1.675 |
| Diaspore | Biaxial (+) | — | 0.048 | 1.702–1.752 |
| Enstatite | Biaxial (+) | — | 0.010 | 1.663–1.673 |
| Hiddenite | Biaxial (+) | — | 0.016 | 1.660–1.676 |
| Kunzite | Biaxial (+) | — | 0.016 | 1.660–1.676 |
| Labradorite | Biaxial (+) | — | 0.011 | 1.559–1.573 |
| Larimar | Biaxial (+) | — | 0.040 | 1.595–1.640 |
| Peridot | Biaxial (+) | — | 0.036 | 1.654–1.690 |
| Prehnite | Biaxial (+) | — | 0.030 | 1.611–1.665 |
| Rhodonite | Biaxial (+) | — | 0.014 | 1.716–1.752 |
| Sphene | Biaxial (+) | — | 0.100 | 1.843–2.110 |
| Star Diopside | Biaxial (+) | — | 0.030 | 1.664–1.721 |
| Tanzanite | Biaxial (+) | — | 0.009 | 1.691–1.700 |
| Thulite | Biaxial (+) | — | 0.009 | 1.691–1.704 |
| Topaz | Biaxial (+) | — | 0.008 | 1.609–1.643 |
| Amazonite | Biaxial (−) | — | 0.008 | 1.514–1.530 |
| Andalusite | Biaxial (−) | — | 0.010 | 1.629–1.649 |
| Danburite | Biaxial (−) | — | 0.006 | 1.627–1.636 |
| Grandidierite | Biaxial (−) | — | 0.033 | 1.590–1.623 |
| Iolite | Biaxial (−) | — | 0.012 | 1.540–1.560 |
| Kornerupine | Biaxial (−) | — | 0.013 | 1.660–1.699 |
| Kyanite | Biaxial (−) | — | 0.016 | 1.712–1.734 |
| Malachite | Biaxial (−) | — | 0.254 | 1.655–1.909 |
| Moonstone | Biaxial (−) | — | 0.008 | 1.518–1.526 |
| Rainbow Moonstone | Biaxial (−) | — | 0.011 | 1.559–1.572 |
| Sinhalite | Biaxial (−) | — | 0.038 | 1.665–1.712 |
| Sunstone | Biaxial (−) | — | 0.010 | 1.537–1.572 |
| Variscite | Biaxial (−) | — | 0.031 | 1.560–1.594 |
| Agate | Agrégat | — | — | 1.530–1.543 |
| Aventurine | Agrégat | — | — | 1.544–1.553 |
| Bloodstone | Agrégat | — | — | 1.530–1.543 |
| Carnelian | Agrégat | — | — | 1.530–1.543 |
| Chalcedony | Agrégat | — | — | 1.530–1.543 |
| Charoite | Agrégat | — | — | 1.550–1.559 |
| Chrysocolla | Agrégat | — | — | 1.575–1.635 |
| Chrysocolla Chalcedony | Agrégat | — | — | 1.530–1.543 |
| Chrysoprase | Agrégat | — | — | 1.530–1.543 |
| Coral | Agrégat | — | — | 1.486–1.658 |
| Hawk's Eye | Agrégat | — | — | 1.544–1.553 |
| Howlite | Agrégat | — | — | 1.583–1.608 |
| Ivory | Agrégat | — | — | 1.535–1.540 |
| Jadeite | Agrégat | — | — | 1.654–1.688 |
| Lapis Lazuli | Agrégat | — | — | 1.500–1.670 |
| Nephrite | Agrégat | — | — | 1.600–1.627 |
| Onyx | Agrégat | — | — | 1.530–1.543 |
| Pearl | Agrégat | — | — | 1.520–1.690 |
| Pietersite | Agrégat | — | — | 1.534–1.540 |
| Serpentine | Agrégat | — | — | 1.560–1.571 |
| Sodalite | Agrégat | — | — | 1.483–1.487 |
| Tiger's Eye | Agrégat | — | — | 1.544–1.553 |
| Turquoise | Agrégat | — | — | 1.610–1.650 |
Quelles gemmes montrent une biréfringence anomale (ADR) ?
22 espèces de ce tableau portent la mention ADR, surtout les grenats et le diamant. Une pierre SR sous contrainte peut montrer une extinction irrégulière qui imite le clignotement DR : confirmez au réfractomètre avant d'écarter les candidates SR.
Le diamant est-il monoréfringent ou biréfringent ?
Monoréfringent (système cubique), mais signalé ADR : les tensions internes produisent très souvent une extinction anomale au polariscope. Cette combinaison est en elle-même caractéristique du diamant.
Que signifient uniaxe et biaxe ?
Les pierres uniaxes (quadratique, hexagonal, rhomboédrique : quartz, corindon, tourmaline) ont un axe optique ; les biaxes (orthorhombique, monoclinique, triclinique : topaze, péridot, tanzanite) en ont deux.Chacune porte un signe, + ou −.
Voir aussi: Reference Database (EN) · Guide (EN)