Garnets, many varieties. See Group D below. Almandine 4.11 and occasionally to 4.25 Ruby 4.073 " 4.080 Sapphire 4.049 " 4.060 Corundum 3.90 " 4.16 Cape Ruby 3.861 Demantoid 3.815 Staurolite 3.735 Malachite 3.710 and occasionally to 3.996 _Group_ C.--Stones whose specific gravity lies between 3.50 and under 3.70. Pyrope (average) 3.682 Chrysoberyl 3.689 and occasionally to 3.752 Spinel 3.614 " 3.654 Kyanite 3.609 " 3.688 Hessonite 3.603 " 3.651 Diamond 3.502 " 3.564 Topaz 3.500 " 3.520 _Group_ D.--Stones whose specific gravity lies between 3 and under 3.50. Rhodonite 3.413 and occasionally to 3.617 Garnets 3.400 " 4.500 Epidote 3.360 " 3.480 Sphene 3.348 and occasionally to 3.420 Idocrase 3.346 " 3.410 Olivine 3.334 " 3.368 Chrysolite 3.316 " 3.528 Jade 3.300 " 3.381 Jadeite 3.299 Axinite 3.295 Dioptase 3.289 Diopside 2.279 Tourmaline (yellow) 3.210 Andalusite 3.204 Apatite 3.190 Tourmaline (Blue and Violet) 3.160 Tourmaline (Green) 3.148 " (Red) 3.100 Spodumene 3.130 and occasionally to 3.200 Euclase 3.090 Fluorspar 3.031 and occasionally to 3.200 Tourmaline (Colourless) 3.029 Tourmaline (Blush Rose) 3.024 Tourmaline (Black) 3.024 and occasionally to 3.300 Nephrite 3.019 _Group_ E.--Stones whose specific gravity lies between 2.50 and under 3.000. Phenakite 2.965 Turquoise 2.800 Beryl 2.709 and occasionally to 2.81 Aquamarine 2.701 " 2.80 Labradorite 2.700 Emerald 2.690 Quartz 2.670 Chrysoprase 2.670 Jasper 2.668 Amethyst 2.661 Hornstone 2.658 Citrine 2.658 Cordierite 2.641 Agate 2.610 Chalcedony 2.598 and occasionally to 2.610 Adularia 2.567 Rock-crystal 2.521 and occasionally to 2.795 _Group_ F.--Stones whose specific gravity lies between 2.00 and under 2.50. Haueynite 2.470 and occasionally to 2.491 Lapis lazuli 2.461 Moldavite 2.354 Opal 2.160 and according to variety to 2.283 " (Fire Opal) 2.210 (average) _Group_ G.--Stones whose specific gravity is under 2.00. Jet 1.348 Amber 1.000 (See also list of stones, arranged in their respective colours, in Chapter XII.)