You may specify these settings as the Refractive Index setting in the Materials panel.
Gemstones
Agate 1.544 - 1.553
Alexandrite 1.746 - 1.755
Almandine 1.75 - 1.83
Amber 1.539 - 1.545
Amethyst 1.532 - 1.554
Ammolite 1.52 -1.68
Andalusite 1.629 - 1.650
Apatite 1.632 - 1.42
Aquamarine 1.567-1.590
Axenite 1.674 - 1.704
Beryl 1.57 - 1.60
Beryl, Red 1.570 - 1.598
Chalcedony 1.544 - 1.553
Chrome Tourmaline, 1.61 - 1.64
Citrine 1.532 - 1.554
Clinohumite 1.625 - 1.675
Coral 1.486 - 1.658
Crystal 2.000
Crysoberyl, Catseye 1.746 - 1.755
Danburite 1.627 - 1.641
Diamond 2.417
Emerald 1.560 - 1.605
Emerald Catseye 1.560 - 1.605
Flourite 1.434
Garnet, Grossular 1.72 - 1.80
Garnet, Andradite 1.88 - 1.94
Garnet, Demantiod 1.880 - 1.9
Garnet, Mandarin 1.790 - 1.8
Garnet, Pyrope 1.73 - 1.76
Garnet, Rhodolite 1.740 - 1.770
Garnet, Tsavorite 1.739 - 1.744
Garnet, Uvarovite 1.74 - 1.87
Hauyn 1.490 - 1.505
Iolite 1.522 - 1.578
Jade, Jadeite 1.64 - 1.667
Jade, Nephrite 1.600 - 1.641
Jet 1.660
Kunzite 1.660 - 1.676
Labradorite 1.560 - 1.572
Lapis Lazuli 1.50 - 1.55
Moonstone 1.518 - 1.526
Morganite 1.585 - 1.594
Obsidian 1.50
Opal, Black 1.440 - 1.460
Opal, Fire 1.430 - 1.460
Opal, White 1.440 - 1.460
Oregon Sunstone 1.560 - 1.572
Padparadja 1.760 - 1.773
Pearl 1.53 - 1.69
Peridot 1.635 - 1.690
Quartz 1.544 - 1.553
Ruby 1.757 - 1.779
Sapphire 1.757 - 1.779
Sapphire, Star 1.760 - 1.773
Spessarite 1.79 - 1.81
Spinel 1.712 - 1.717
Spinel, Blue 1.712 - 1.747
Spinel, Red 1.708 - 1.735
Star Ruby 1.76 - 1.773
Tanzanite 1.690-1.7
Tanzanite 1.692 - 1.700
Topaz 1.607 - 1.627
Topaz, Imperial 1.605-1.640
Tourmaline 1.603 - 1.655
Tourmaline, Blue 1.61 - 1.64
Tourmaline, Catseye 1.61 - 1.64
Tourmaline, Green 1.61 - 1.64
Tourmaline, Paraiba 1.61 - 1.65
Tourmaline, Red 1.61 - 1.64
Zircon 1.777 - 1.987
Zirconia, Cubic 2.173 - 2.21
Common Liquids
Acetone 1.36
Alcohol, Ethyl (grain) 1.36
Alcohol, Methyl (wood) 1.329
Beer 1.345
Carbonated Beverages 1.34 - 1.356
Fruit Juice
Chlorine (liq) 1.385
Cranberry Juice (25%) 1.351
Glycerin 1.473
Honey, 13% water content 1.504
Honey, 17% water content 1.494
Honey, 21% water content 1.484
Ice 1.309
Milk 1.35
Oil, Clove 1.535
Oil, Lemon 1.481
Oil, Neroli 1.482
Oil, Orange 1.473
Oil, Safflower 1.466
Oil, vegetable (50 C) 1.47
Oil of Wintergreen 1.536
Rum, White 1.361
Shampoo 1.362
Sugar Solution 30% 1.38
Sugar Solution 80% 1.49
Turpentine 1.472
Vodka 1.363
Water (0 C) 1.33346
Water (100 C) 1.31766
Water (20 C) 1.33283
Whisky 1.356<
Common Transparent Materials
Eye, Aqueous humor 1.33
Eye, Cornea 1.38
Eye, Lens 1.41
Eye, Vitreous humor 1.34
Glass, Arsenic Trisulfide 2.04
Glass, Crown (common) 1.52
Glass, Flint, 29% lead 1.569
Glass, Flint, 55% lead 1.669
Glass, Flint, 71% lead 1.805
Glass, Fused Silica 1.459
Glass, Pyrex 1.474
Lucite 1.495
Nylon 1.53
Obsidian 1.50
Plastic 1.460 - 1.55
Plexiglas 1.488
Salt 1.516