524 REPORT OF NATIONAL MUSEUM, 1900. 



Bloodstone or heliotrope. — A translucent to opaque jasper of a deep- 

 green color inter.sper.sed with red .spots. 



Caii'ngoi'm, smol'y quartz, or niorlon. — Having a smoky gra}', 3'ellow, 

 yellowish -brown, and brown color. The crystals are often pellucid, 

 but occasionally the color is so deep as to render then) nearly opaque. 



Carnelian. — A reddi.sh variet}' of chalcedony passing into grayish 

 red, 3'ellow, and l)rown; translucent, like horn. The carnelian takes a 

 fine polish and is often of a clear bright tint. The colors are commonly 

 heightened l)y exposure to the sun or b}' heat. (Plate 6.) 



Cafs-eye. — Translucent quartz exhibiting opalescence or chatoj^ancy 

 when cut cabochon, an effect due to inclusions of fibrous minerals, such 

 as hornl)lende, asbestus, actinolite, and crocidolite. The color is com- 

 monl}' light greenish gray; sometimes yellow, red, or brownish. 



Chalcedony. — Translucent, subtranslucent, or opaque, usually having 

 a waxy luster and a white, yellow, brown, or bluish color. It occurs 

 massive in imitative shapes. 



Chryso2)rase. — An apple, leek-green, bluish, or yellowish translucent 

 chalcedony. 



Citrine quartz, false, Saxon, Scotch, or Spanish topaz.— K. light- 

 yellow, brown, or greenish-yellow, pellucid quartz. 



Ferruginous quartz, ruh<(sst, Ancona ruhy, or 2Iont Blanc ruby, is 

 opaque-red, brownish-red, or ocher-yellow crj^stallized quartz. 



Flint. — A more or less opaque chalcedonic quartz, usuall}' g'l'^^y^ 

 smoke brown, and brownish black. "Breaks with a conchoidal fracture 

 and a sharp cutting edge. 



Jlornstone closely resembles flint, but has a more splintery fracture. 



Hyaline is an opalescent white quartz. 



Jasper. — An impure massive quartz or chalcedonic rock, presenting 

 little beauty until polished. Color, dull red, yellow, brown, or green, 

 sometimes blue or black. AVhen the colors are ])anded it is called rih- 

 l>and jasjjer. If zoned with colors, yellow, red, brown, or black, it is 

 called Egyptian jaspjer. Jasper takes a high polish, and is extensively 

 used in the manufacture of mosaics, vases, snufl:' and match boxes, 

 knife handles, etc. 



Milky quartz is a massive, vitreous variety, having a milk-white color. 

 It is occasionalh' opalescent, and sometimes has a greasy- luster. 



Moss agate w mocha stone is a chalcedony, containing dendritic or 

 moss-like markings. 



Onyx. — Ijike agate, but the colors are arranged in horizontal planes 

 or layers, so that it can be used in cutting cameos. When the laj^ers 

 consist of reddish and white chalcedony the stone is called sardonyx. 



Plasma. — A more or less translucent chalcedony, having a leaf -green 

 color. 



Prase. — A leek or olive green, somewhat spotted, massive quartz. 



Roch cjnjstal. — Transparent and colorless; includes the pure crystals 

 of quartz. 



