438 NATURAL HISTORY. 



is a valuable gem ; the scarlet crystal is called Spinel 

 Ruby; the rose-red, Balas Ruby; the pale-colored are 

 less esteemed ; the dark-colored crystals, brown or 

 blackish, are known as Ceylonites. Found in Ceylon 

 and Peru ; occurs in dolomite, limestone, and gneiss. 



Chrysolite Olivine is what is called Pistachio or 

 asparagus green, seldom yellow or brown. Luster vit- 

 reous, transparent, often only translucent. Occurs in 

 prismatic crystals, or in compact, imbedded grains. 

 II. = 6.5 to 7.0. G. = 3.3 to 3.5. ' Found in Egypt, 

 Brazil, Bohemia, and Saxony; occurs discriminated in 

 basalt, lavas, and meteoric iron, and is a characteristic 

 mineral of these rocks. The brighter colored chrysolites 

 are sometimes used as gems, but upon the whole, are 

 little valued, and seldom employed for any purpose. 



II. Speckstein True Talc or Spanish Chalk has 

 an unctuous or dry soapy feel and eminently pearly lus- 

 ter, translucent on the edges; color mostly white, also 

 gray, green, or reddish, sometimes arborescent or marked 

 with radiating lines. Shines like soap on being rubbed ; 

 does not adhere to the tongue. Fracture uneven, splin- 

 tery, or separating into thin translucent folia. H. = 1.0 

 to 2.0. G. = 2.6 to 2.8. Occurs in the serpentine 

 rocks of Sweden, France, Germany, and also United 

 States, and known as talcose slate or steatite. Impress- 

 ible by the nail. If used for writing on glass, the im- 

 pression is so permanent, that after being wiped off and 

 the spot breathed upon, the inscription is as plain as at 

 first. 



Serpentine rarely occurs in right rectangular prisms, 

 but is usually massive and compact in texture ; translu- 

 cent on the edges, nearly opaque : feels slightly oily ; 

 color white, yellow, red, but mostly green, in veins or 



