_Specific Gravity._
(See Chapter VII.) (See Chapter VIII.)
Aquamarine 7-3/4 2.701-2.800
Chrysoberyl 8-1/2 3.689-3.752
Chrysolite 6-7 3.316-3.528
Chrysoprase (Quartz) 7 2.670
Diamond 10 3.502-3.564
Dioptase 5 3.289
Emerald and Oriental Emerald 7-3/4 2.690
Euclase 7-1/2 3.090
Garnet (see also Red Garnet) 6-1/2-7-1/2 3.400-4.500
Heliotrope (Chalcedony) 6-1/2 2.598-2.610
Hiddenite (a variety of Spodumene) 6-1/2-7 3.130-3.200
Jade 7 3.300-3.381
Jadeite 7 3.299
Malachite 3-1/2 3.710-3.996
Peridot (a variety of Chrysolite) 6-7 3.316-3.528
Plasma (a variety of Chalcedony) 6-1/2 2.598-2.610
Quartz 7 2.670
Sapphire 9 4.049-4.060
Topaz 8 3.500-3.520
Tourmaline 7-1/4 3.148

VIOLET STONES.

_Hardness._ _Specific Gravity._
(See Chapter VII.) (See Chapter VIII.)
Amethyst 7 2.661
Diamond 10 3.502-3.564
Quartz (Amethyst) 7 2.670
Sapphire 9 4.049-4.060
Spinel 8 3.614-3.654
Tourmaline 7-1/4 3.160

CHATOYANT STONES.

These stones are easily recognisable by their play of colour. (See
Chapter XIV.)

BLACK STONES.

_Hardness._ _Specific Gravity._
(See Chapter VII.) (See Chapter VIII.)
Diamond 10 3.502-3.564
Garnet