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Ch. 7: Garnet

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80
PRECIOUS STONES.
specific gravity, etc., it will be advisable to discuss the several varieties used in jewellery separately.
1. Cinnamon stone or Hessonite.—This garnet (generally but incorrectly called essonite) has long been confused with zircon of similar colour—a sort of deep golden hue with a tinge of flame red. All the engraved gems said to be of hyacinth and jacinth— that is, zircon—-are in fact cinnamon stones, or, as they may be called, hyacinthine garnets, not zircons ; we except those which, while resembling cinnamon stone, are only sard. The three species may be discriminated in several ways, the true hyacinthine zircon having, for example, the specific gravity of 4'6, the cinnamon stone 3-7, and the sani 2'66: other criteria are furnished by differences in lustre, harness and refractivity. The best hessonites come from Ceylon : they may be recognised by their peculiar appearance, in a good light, when examined by the aid of a hand magnifier. This appearance is that of a finely granulated texture, as if made up of sard grains barely molten together. The specific gravity of cinnamon stone will be seen, from the following deter­minations, to be fairly constant :—(1) 3'69. (2) 3'657. (3) 3'642. (4) 3'642. (5) 3'666. Grossularite belongs here.
A cinnamon stone from Ceylon gave on analysis these per­centages :—
Antique Roman intaglios on cinnamon stone, both light and dark in tone, are numerous ; cameos are not infrequent. This stone is more easily cut and engraved than the full red varieties of garnet, having indeed a degree of hardness very near that of quartz, instead of quite half a degree above it.
2. Almandine, carbuncle, precious garnet.—The range of colour in this variety of garnet lies between a violet or purple near that of the amethyst and a brownish red or reddish brown. The pure
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