332 GEORGE F. KUNZ 



This may prove to be a source of choice gem material, although 

 as yet the amount of it present has not been ascertained. 



Tourmaline belongs to the rhombohedral system of crys- 

 taUization, occurring in prisms, the sides of which are generally 

 striated and channeled. The transparent variety is of a hard- 

 ness of 7.5, its specific gravity ranges from 3 to 3.25, and m 

 composition it is a very complex siUcate of aluminia. Many 

 different colors are found, ranging all the way from a colorless 

 variety through red, green, blue, and brown, to black. These 

 differences in color are chiefly due to the varying amounts of 

 manganese and iron present. The gem is dichroitic; thus 

 when viewed from the side it may be a transparent green, but 

 either opaque or yellow green when viewed endwise of the 



prism. 



Tourmahne was but little known in jewelry ten years ago, 

 although some very beautiful gems had been cut from the trans- 

 parent red, green and blue crystals obtained at Paris Hill, Me., 

 and at Haddam Neck, Conn. Some mining had been done 

 at these places, and many splendid specimens obtained. But 

 within a few years past, wonderful discoveries of gem 

 tourmaline have been made in southern Cahf ornia, at Pala and 

 Mesa Grande, in San Diego county, and in the San Jacinto 

 mountains in Riverside County. The crystals found at these 

 locahties are of great size and beauty, and gems have been cut 

 from them in abundance. A single collection of these crystals 

 has been valued at $10,000. The prevaihng colors are pink, 

 salmon and red, all in very rich shades, also fine green and blue, 

 though less frequently in these colors than those found at 

 Mt. Mica and other locahties near Paris, Me. Tourmahne is 

 pecuhar in that it often presents two or three different and 

 even contrasting colors in the same crystal, which sometimes 

 shade into each other, but often present a sharp hne of contact. 

 Advantage has been taken of this feature, which is marked in 

 the Cahfornia crystals, to produce in jewelry the novelty of 

 parti-colored gems. Beautiful cut stones may now be seen that 

 are half red and half green, or showing other similar contrasts. 



There are two mines at Pala, Cal., owned by the Pala 

 Lithia company, one of which yields beautiful specimens of 

 rather small and opaque pink tourmahne crystals, in radiated 



