98 DESCRIPTIONS OF MINERALS. 



G-.=1'48. Composition, H 6 6 Bo 2 = Boron teroxide 56*4, 

 water 43 "6. It is strictly hydrogen borate. Fuses easily 

 in the flame of a candle, tinging the flame at first green. 



Found at the crater of Vulcano, and also at Sassoin Italy, 

 whence it was called Sassolin. The hot vapors of the la- 

 goons of Tuscany afford it in large quantities. The vapors 

 are made to pass through water, which condenses them ; and 

 the water is then evaporated by the steam of the springs, 

 and boraoic acid obtained in large crystalline flake's. It 

 still requires purification, as the best thus procured contains 

 but 50 per cent, of the pure acid. Occurs also in the waters 

 of Lick Springs, Tehama Co., and Borax Lake, Lake Co., 

 California, where it was first observed, through their evapo- 

 ration, by Dr. J. A. Veatch, in 1856. It has since been 

 obtained from the waters of Mono, Owens, and other lakes. 

 It exists sparingly in the waters of the ocean. But in all 

 these waters, it is probably in combination. 



Boron occurs usually in the condition of magnesium, calcium, and 

 sodium borates (pp. 206, 212, 227) ; and rarely as an iron borate (p. 182), 

 or ammonium borate (p. 231). It also occurs in the silicates, tourma- 

 line, danburite, axinite, and datolite, in which it is easily detected by 

 the blowpipe reaction (p. 87). 



III. THE ARSENIC GROUP. 



The elements of the Arsenic group occurring among 

 minerals are, arsenic, antimony, bismuth, phosphorus, ni- 

 trogen, vanadium, tantalum, columbium. Of these arsenic, 

 antimony, and bismuth occur native, and as sulphides ; also, 

 in combination with other metals, constituting arsenides, 

 antimonides, bismutides ; and, along with sulphur also, mak- 

 ing sulpharsenites, sulphantimonites, sulphbismutites. In 

 addition, they all, excepting bismuth, enter into the consti- 

 tution of a series of native ternary oxygen compounds or 

 salts, called severally, arsenates, antimonates, phosphates, 

 nitrates, vanadates, tantalates, columbates. 



The chief oxide has the general formula E 2 5 . 



Native Arsenic. 



Rhombohedral. RaB=S5° 41'. Cleavage basal, imper- 

 fect. Also massive, columnar, or granular. 



