California Art & Nature. 



of 20 or 30 feet, while the same quartz 

 crystallizes in its beautiful and definite 

 but colorless forms in the depths of the 

 deepest mines. The diamond and the 

 sapphire belong to superficial terrains; 

 and we find that the rule of shallow 

 deposit relates to most of the gems. 

 The topaz of Braz.il, the beryl of Si- 

 beria, the chrysoprase of Silesia, the 

 turquoise of Thibet, or the opals of 

 Hungary, all occur near the surface of 

 the earth, and are never found below 

 a certain depth.' 



Oliver Cummings Farrington, in 

 Birds and Nature for September, 1901, 

 says: — 



'The crystals are usually in the form 

 of long, slender prisms; They often 

 have the peculiarity of being differ- 

 ently colored in different portions. 

 Thus a crystal may be green at one end 

 and red at the other, and in cross sec- 

 tion may show a blue center, then a 

 colorless zone, then one of red and 

 then one of green. Some of the crystals 

 from Paris, Me., change from white 

 at one termination to emerald green, 

 then lightl green, then pink, and finally 

 colorless at the other termination. In 

 some crystals again the red passes to 

 blue, the blue to green and the green 

 to black. 



Tourmalines of different colors have 

 been known in the mountains near San 

 Diego, California, for many years. At 

 Pala the red crystals in lepidolite have 

 been known since 1876, but not until 

 1898 was this remarkable deposit of 

 lithia mica of known value, when the 

 writer brought it to the attention of 

 great chemical houses. The beautiful 

 radiations of red tourmaline crystals 

 in the delicate lilac lepidolite are sel- 

 dom of gem value, but are now to be 

 found in nearly every mineral cabinet 

 in the world. 



At Mesa Grande, east of San Diego, 

 one of the most remarkable deposits of 

 tourmalines was brought to my notice 

 in 1899. The locality had been known 

 for nearly 20 years, but had previously 

 failed to attract attention. In 1900 the 

 mine produced hundreds of crystals 

 from 1 to 2 inches in diameter, gener- 

 ally 3 or 4 inches or more long, of 

 nearly every shade and tint of color 

 that the world had yet known, except 

 some shades of blue and yellow. 



A vein of feldspathic minerals, 

 mostly decomposed, and lying on a 

 granite foundation, contained masses 

 of coarse, purple lepidolite, angular 

 fragments of crystal quartz, and am- 

 blygonite, spodumene, and other min- 

 erals. In this matrix were the beau- 

 tiful vari-colored crystals of tourma- 

 lines, and loose in the soil composed of 

 decomposed portions of the ledge, were 

 many of the finest gems ever found. 

 C. R. ORCUTT. 



OACTI AT HOME. 



CASSITERITE — Tin stone from 

 Cornwall, England, is composed of 78.6 

 per cent tin, and 21.4 per cent oxygen. 

 It occurs in the Black Hills, South Da- 

 kota, at Temescal, Riverside county, 

 California, and near San Diego. The 

 two latter localities may yield speci- 

 mens equal to that from Durango, 

 Mexico, which is polished as a gem. 



