Diamonds and precious stones, a popular account of gems .. (1874)
Dieulafait, Louis, b. 1830, Sanford, Fanchon, tr · New York, Scribner, Armstrong, and Company · leaf 170
ve mentioned, are formed principally ofsilica: here indeed we would naturally look forthem; but that which would seem much less pro-bable, and yet actually occurs, is the presence of QUARTZ. 149 magnificent crystals of quartz, of an absolute purity,in the midst of rocks nearly exempt from all… … Figs. 69 and 70.—Modified Crystals of Quartz. the other, oxygen, is a gas, and one of the principalconstituents of atmospheric air. The primitive form of quartz is the rhombohedron,but the primitive crystals are extremely rare. Themost common form is the regular hexagonal prismterminated with…
Precious stones · Diamonds · Gems
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