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Ch. 6: Ruby, Sapphire, Spinel etc.

Ch. 6: Ruby, Sapphire, Spinel etc. Page of 295 Ch. 6: Ruby, Sapphire, Spinel etc. Text size:minus plus Restore normal size   Mail page  Print this page
116 The Chrysoberyl, Cymophane, etc.
yellow, or brownish-yellow colour, occasionally white ; some varieties showing a reddish tint by transmitted light. Some specimens possess an opalescence, and these are generally cut en cabochon, when they are called chrysolite, or chrysoberyl cat's-eye, or cymophanes.
It belongs to the trimetric or rhombic system of crys­tallization, and possesses a vitreous lustre ; it varies from being perfectly transparent to nearly opaque ; its cleavage is not very perfect, and it breaks with a conchoidal frac­ture rather uneven ; its specific gravity varies from 3'68o to 3.754, and its hardness is numbered in the scale as 8-5, being scratched by the sapphire, ruby, etc., and scratching quartz easily. It possesses double refraction to a high degree, and acquires positive electricity by fric­tion, retaining it for several hours.
It is infusible before the blowpipe alone, but melts with difficulty to a clear glass with borax or salt of phosphorus. It is not affected by acids.
Its chemical composition is—
with traces of protoxide of iron, oxides of lead and cop­per, according to colour and locality where found.
This gem is found in rolled pebbles in the alluvial deposits of rivers in Ceylon, near Saffragang, in the Rio Americanas and Rio Piantic in Brazil, at Marchenberg and Petersdorf, near Weisenberg, in Moravia ; also im­bedded in mica slate in the river Tajow.-rja in the Ural
Ch. 6: Ruby, Sapphire, Spinel etc. Page of 295 Ch. 6: Ruby, Sapphire, Spinel etc.
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