Table of Refractive Index and Double Refraction of Gems

Gemstone Refractive Index Double Refraction
Hematite 2.940 – 3.220 0.287
Cinnabar 2.905 – 3.256 0.351
Proustite 2.881 – 3.084 0.203
Pyrargyrite 2.88 – 3.08 0.200
Cuprite 2.849 none
Rutile 2.616 – 2.903 0.287
Brookite 2.583 – 2.700 0.117
Anatase 2.488 – 2.564 0.046 – 0.067
Diamond 2.417 – 2.419 anomalous
Fabulite 2.409 none
Stibiotantalite 2.370 – 2.450 0.080
Sphalerite 2.368 – 2.371 none
Crocoite 2.29 – 2.66 0.270
Wulfenite 2.280 – 2.400 0.120
Tantalite 2.26 – 2.43 0.160
Linobate 2.21 – 2.30 0.090
Manganotantalite 2.19 – 2.34 0.150
Zirconia 2.150 – 2.180 none
Mimetite 2.120 – 2.135 0.015
Phosgenite 2.114 – 2.145 0.028
Senarmontite 2.087 none
Boleite 2.03 – 2.05 0.020
Zincite 2.013 – 2.029 0.016
Cassiterite 1.997 – 2.098 0.096 – 0.098
Simpsonite 1.994 – 2.040 0.058
GGG 1.970 – 2.020 0.058
Sulphur 1.958 – 2.245 0.291
Bayldonite 1.95 – 1.99 0.04
Scheelite 1.918 – 1.937 0.010 – 0.018
Andradite 1.88 – 1.94 none
Anglesite 1.878 – 1.895 0.017
Uvarovite 1.865 none
Purpurite 1.85 – 1.92 0.007
Titanite 1.843 – 2.110 0.100 – 0.192
YAG 1.833 – 1.835 none
Zircon 1.810 – 2.024 0.0002 – 0.059
Cerussite 1.804 – 2.079 0.274
Gahnite 1.791 – 1.818 none
Spessartine 1.790 – 1.820 none
Painite 1.787 – 1.816 0.029
Monazite 1.774 – 1.849 0.049 – 0.055
Almandine 1.770 – 1.820 none
Gadolinite 1.77 – 1.82 0.01 – 0.04
Ruby 1.762 -1.778 0.008
Sapphire 1.762 -1.778 0.008
Benitoite 1.757 – 1.804 0.047
Shattuckite 1.752 – 1.815 0.063
Chrysoberyl 1.746 – 1.763 0.007 – 0.011
Periclase 1.74 none
Scorodite 1.738 – 1.816 0.027 – 0.030
Staurolite 1.736 – 1.762 0.010 – 0.015
Grossular 1.734 – 1.759 none
Chambersite 1.732 – 1.744 0.012
Hessonite 1.730 – 1.757 none
Epidote 1.729 – 1.768 0.015 – 0.049
Pyroxmangite 1.726 – 1.764 0.016 – 0.020
Azurite 1.720 – 1.848 0.108 – 0.110
Pyrope 1.720 – 1.756 none
Hodgkinsonite 1.719 – 1.748 0.022 – 0.026
Taaffeite 1.719 – 1.730 0.004 – 0.009
Rhodonite 1.716 – 1.752 0.010 – 0.014
Gahnospinel 1.715 – 1.754 none
Spinel 1.712 – 1.762 none
Kyanite 1.710 – 1.734 0.015 – 0.033
Adamite 1.708 – 1.760 0.048 – 0.050
Diaspore 1.702 – 1.750 0.048
Serendibite 1.701 – 1.743 0.005
Sapphirine 1.701 – 1.734 0.004 – 0.007
Aegirine-augite 1.700 – 1.800 0.030 – 0.050
Vesuvianite 1.700 – 1.723 0.002 – 0.012
Tanzanite 1.691 – 1.700 0.009
Neptunite 1.690 – 1.736 0.029 – 0.045
Willemite 1.690 – 1.723 0.028 – 0.033
Rhodizite 1.690 none
Triphylite 1.689 – 1.702 0.006 – 0.008
Lithiophilite 1.68 – 1.70 0.01
Dumortierite 1.678 – 1.689 0.015 – 0.037
Legrandite 1.675 – 1.740 0.060
Hypersthene 1.673 – 1.731 0.010 – 0.016
Parisite 1.671 – 1.772 0.081 – 0.101
Clinozoisite 1.670 – 1.734 0.010
Sinhalite 1.665 – 1.712 0.036 – 0.042
Lawsonite 1.665 – 1.686 0.019 – 0.021
Diopside 1.664 – 1.730 0.024 – 0.031
Bustamite 1.662 – 1.707 0.014 – 0.015
Cornerupine 1.660 – 1.699 0.012 – 0.017
Hiddenite 1.660 – 1.681 0.014 – 0.016
Kunzite 1.660 – 1.681 0.014 – 0.016
Boracite 1.658 – 1.673 0.010 – 0.011
Axinite 1.656 – 1.704 0.010 – 0.012
Malachite 1.655 – 1.909 0.254
Sillimanite 1.655 – 1.684 0.014 – 0.021
Jadeite 1.652 – 1.688 0.20
Peridot 1.650 – 1.703 0.036 – 0.038
Ludlamite 1.650 – 1.697 0.038 – 0.044
Enstatite 1.650 – 1.680 0.009 – 0.012
Euclase 1.650 – 1.677 0.019 – 0.025
Phenakite 1.650 – 1.670 0.016
Dioptase 1.644 – 1.709 0.051 – 0.053
Jet 1.640 – 1.680 none
Eosphorite 1.638 – 1.671 0.028 – 0.035
Spurrite 1.637 – 1.681 0.039 – 0.040
Jeremejevite 1.637 0 1.653 0.007 – 0.013
Baryte 1.636 – 1.648 0.012
Siderite 1.633 – 1.875 0.242
Danburite 1.630 – 1.636 0.006 – 0.008
Clinohumite 1.629 – 1.674 0.028 – 0.041
Apatite 1.628 – 1.649 0.002 – 0.006
Andalusite 1.627 – 1.649 0.007 – 0.013
Friedelite 1.625 -1.664 0.030
Smithsonite 1.621 – 1.849 0.228
Datolite 1.621 – 1.675 0.040 – 0.050
Celestine 1.619 – 1.635 0.010 – 0.012
Tourmaline 1.614 – 1.666 0.014 – 0.032
Actinolite 1.614 – 1.653 0.020 – 0.025
Hemimorphite 1.614 – 1.636 0.022
Lazulite 1.612 – 1.646 0.031 – 0.036
Prehnite 1.611 – 1.669 0.021 – 0.039
Gaspéite 1.61 – 1.81 0.22
Turquoise 1.610 – 1.650 0.040
Topaz 1.609 – 1.643 0.008 – 0.016
Sugilite 1.607 – 1.611 0.001 – 0.004
Sogdianite 1.606 – 1.608 0.002
Brazilianite 1.602 – 1.623 0.019 – 0.021
Rhodochrosite 1.600 – 1.820 0.208 – 0.220
Odontolite 1.60 – 1.64 0.010
Nephrite 1.600 – 1.627 0.027
Pectolite 1.595 – 1.645 0.038
Montebrasite 1.594 -1.633 0.22
Phosphophyllite 1.594 – 1.621 0.021 – 0.033
Meliphanite 1.593 – 1.612 0.019
Eudialyte 1.591 -1.633 0.003 – 0.010
Chondrodite 1.592 – 1.646 0.028 – 0.034
Catapleiite 1.590 – 1.629 0.039
Wardite 1.590 – 1.599 0.009
Herderite 1.587 – 1.627 0.023 – 0.032
Colemanite 1.586 – 1.615 0.028 – 0.030
Howlite 1.586 – 1.605 0.019
Zektzerite 1.582 – 1.585 0.003
Amblygonite 1.578 – 1.646 0.024 – 0.030
Ekanite 1.572 – 1.573 0.001
Anhydrite 1.570 – 1.614 0.044
Augelite 1.570 – 1.590 0.014 – 0.020
Emerald 1.565 – 1.602 0.006
Aquamarine 1.564 – 1.596 0.004 – 0.005
Variscite 1.563 – 1.594 0.031
Precious Beryl 1.562 – 1.602 0.004 – 0.010
Tremolite 1.560 – 1.643 0.017 – 0.027
Vivianite 1.560 – 1.640 0.050 – 0.075
Serpentine 1.560 – 1.571 0.008 – 0.014
Larbradorite 1.559 – 1.570 0.008 – 0.010
Hambergite 1.553 – 1.628 0.072
Pyrophyllite 1.552 – 1.600 0.048
Muscovite 1.552 – 1.618 0.036 – 0.043
Beryllonite 1.552 – 1.561 0.009
Charoite 1.550 – 1.561 0.004 – 0.009
Amethyst 1.544 – 1.553 0.009
Aventurine 1.544 – 1.553 0.009
Rock Crystal 1.544 – 1.553 0.009
Citrine 1.544 – 1.553 0.009
Prasiolite 1.544 – 1.553 0.009
Smoky quartz 1.544 – 1.553 0.009
Rose quartz 1.544 – 1.553 0.009
Andesine 1.543 – 1.551 0.008
Cordierite 1.542 – 1.578 0.008 – 0.012
Oligoclase 1.542 – 1.549 0.007
Talc 1.54 – 1.59 0.050
Scapolite 1.540 – 1.579 0.006 – 0.037
Amethyst 1.54 – 1.55 0009 Quartz
Petrified Wood 1.54 none
Jasper 1.54 none
Amber 1.539 – 1.545 none
Ivory 1.535 – 1.570 none
Apophyllite 1.535 – 1.537 0.002
Tiger’s-eye 1.534 – 1.540 none
Aragonite 1.530 – 1.685 0.155
Agate 1.530 -1.540 0.004 – 0.009
Chalcedony 1.530 -1.540 0.004 – 0.009
Chrysoprase 1.530 -1.540 0.004 – 0.009
Moss agate 1.530 -1.540 0.004 – 0.009
Sepiolite 1.53 none
Witherite 1.529 – 1.677 0.148
Milarite 1.529 -1.551 0.003
Nepheline 1.526 – 1.546 0.0004
Sunstone 1.525 – 1.548 0.01
Amazonite 1.522 – 1.530 0.008
Pearl 1.52 – 1.69 0.156
Ammonite 1.52 – 1.68 0.155
Strontianite 1.52 – 1.67 0.150
Gypsum 1.520 – 1.529 0.009
Orthoclase 1.518 – 1.530 0.008
Sanidine 1.518 – 1.530 0.008
Moonstone 1.518 – 1.526 0.008
Pollucite 1.517 – 1.525 none
Carletonite 1.517 – 1.521 0.004
Stichtite 1.516 – 1.544 0.026
Thomsonite 1.515 – 1.542 0.006 – 0.025
Magnesite 1.509 – 1.717 0.022
Scolecite 1.509 – 1.525 0.007 – 0.012
Leucite 1.504 – 1.509 0.001
Mesolite 1.504 – 1.508 0.001
Dolomite 1.502 – 1.698 0.185
Petalite 1.502 – 1.519 0.012 – 0.017
Lapis Lazuli 1.5 none
Haüyne 1.496 – 1.510 none
Tugtupite 1.496 – 1.502 0.006
Cancrinite 1.495 – 1.528 0.024 – 0.029
Celluloid 1.495 – 1.520 none
Ulexite 1.491 – 1.520 0.029
Yugawaralite 1.490 – 1.509 0.011 – 0.014
Whewellite 1.489 – 1.651 0.159 – 0.163
Kurnakovite 1.488 – 1.525 0.036
Inderite 1.486 – 1.507 0.017 – 0.020
Calcite 1.486 – 1.658 0.172
Coral 1.486 – 1.658 0.160 -0.172
Moldavite 1.48 – 1.54 none
Natrolite 1.480 – 1.493 0.013
Sodalite 1.48 none
Analcime 1.479 – 1.489 none
Thaumasite 1.464 – 1.507 0.036
Creedite 1.461 – 1.485 0.024
Chrysocolla 1.460 – 1.570 0.023 – 0.040
Obsidian 1.45 – 1.55 none
Gaylussite 1.443 – 1.523 0.080
Glass 1.44 – 1.90 none
Flourite 1.434 none
Sellaite 1.378 -1.390 0.012
Opal 1.37 – 1.52 none