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JACINTH.
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115
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various articles, believed to have been used ornamentally by the priestesses of Cybele.
The gagat was used in medicine and alchemy. It was also used in marking fictile vases indelibly in black : " Fictilia ex eo inscritta non delentur."
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XLII.
JACINTH.
This stone, of a fine reddish-yellow colour, is distinguished as either Oriental or Western.
The
Oriental is much more esteemed, and chiefly for its colour and
hardness. It scratches quartz, but is scratched by corundum ; for which
reason it cannot be mistaken for it, although some people have
confounded them.
It comes from Pegu, Ceylon, and Arabia. It is very bright and receives a fine polish, although its light is rather resinous.
It
crystallizes in oblong tetrahedral prisms, terminating in two short
pyramids ; has double refraction, and its specific gravity is from 3-631 to 3-687.
The Western jacinth is, on the contrary, a very common yellow quartz, which is found in Brazil and in France.
In colour it is more yellowish than the Oriental. On analysis it yields
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