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DEMANTOID

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Originally appearing in Volume V07, Page 979 of the 1911 Encyclopedia Britannica.
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DEMANTOID , the name given by Nils Gustaf See also:

Nordenskiold to a See also:green See also:garnet, found in the Urals and used as a See also:gem See also:stone. As it possesses high refractive and dispersive See also:power, it presents when properly cut See also:great brilliancy and " See also:fire," and the name has reference to its See also:diamond-like See also:appearance. It is sometimes known as " Uralian See also:emerald," a rather unfortunate name inasmuch as true emerald is found in the Urals, whilst it not infrequently passes in See also:trade as See also:olivine. Demantoid is regarded as a See also:lime-See also:iron garnet, coloured probably by a small proportion of See also:chromium. The See also:colour varies in different specimens from a vivid green to a dull yellowish-green, or even to a See also:brown. The specific gravity of an emerald-green demantoid was found to be 3'849, and that of a greenish-yellow specimen 3.854 (A. H. See also:Church). The hardness is only 6.5, or See also:lower even than that of quartz—a See also:character rather adverse to the use of demantoid as a gem. This See also:mineral was originally discovered as pebbles in the See also:gold-washings at Nizhne Tagilsk in the Ural Mountains, and was afterwards found in the stream called Bobrovka, in the Sysertsk See also:district on the western slope of the Urals. It occurs not only as pebbles but in the See also:form of granular nodules in a See also:serpentine See also:rock, and occasionally, though very rarely, shows traces of crystal faces. (F.

W.

End of Article: DEMANTOID

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DEMAGOGUE (Gr. Srlµaywybs, from iyety, to lead, an...
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DEMARATUS (Doric Aaµaparos, Ionic Arlµapi ros)