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Ch. 6: Quartz Amethyst

Ch. 6: Quartz Amethyst Page of 515 Ch. 6: Quartz Amethyst Text size:minus plus Restore normal size   Mail page  Print this page
ROCK CRYSTAL.
263
ally employed in jewelry and for ornaments ; but the larger specimens are first assorted and then split or cleaved, and the smaller pieces are sawed through with a copper wire, emery, and oil, into the desired sizes, when they are ready for being cut on copper or leaden discs, with emery and water, and polished on tin plates with rotten-stone, putty, bole, or other fine powder ; or they may be polished on wooden wheels, lined with fur or leather. The forms which they generally receive from the lapidary, are the brilliant, rose, or table. The iridescent quartz, and the hair or needle stones, are only cut concave. Those specimens that have a full pure wine-yellow color, are best cut in steps. When mounted, they are either â jour, or with a black foil. Those which are spotted, or of an irregular.color, may be discolored by careful calcinatici in crucibles, with lime, sand, or pearlash, which process likewise increases the lustre. The crystal may be bored with a diamond point, also engraved, and figures may be etched in it by means of fluoric acid. It is mostly used for pins and rings ; also, for the base of doublets.; likewise, for a very great variety of ornaments, such as seals, gems, snuff-boxes, cane-heads, &c. ; also for imitating the real gems, by being colored and immediately immersed in a solution of coloring water, whereby the color is very closely imitated. It is moreover the base of all the pastes or strass.·
Its value is by no means so high as formerly, when the demand for it was great for setting in buckles, buttons, &c. Articles made of large pieces of it, or those con­taining slender needles, hair, moss, incrustation, or imita­tion of other substances, are yet somewhat esteemed. In their natural state, if quite clear, as they, are received from Madagascar, Switzerland, and Brazil, they are sold for from one to ten dollars per pound ; but when cut for seal-stones, or breastpins, they are sold mostly by the jewellers of this
Ch. 6: Quartz Amethyst Page of 515 Ch. 6: Quartz Amethyst
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