96 DESCRIPTIONS OF MINERALS. 



Sulphuric and Sulphurous Acids. 



Sulphuric acid is occasionally met with around volcanoes, 

 and it is also formed from the decomposition of hydrogen 

 sulphide about sulphur springs. 



It is intensely acid. Composition, Sulphur teroxide (S0 3 ) 

 81*6, water 18 : 4=100, it being chemically hydrogen sul- 

 phate. Occurs in the waters of Kio Vinagre, South America ; 

 also in Java, and at Lake de Taal on Luzon, in the East 

 Indies ; in Genesee Co., N. Y. ; and at Tuscarora, St. Davids, 

 and elsewhere, Canada West. 



Sulphurous acid, or sulphur dioxide (SO.,), is produced 

 when sulphur burns, and causes the odor perceived during 

 the combustion. It is common about active volcanoes. It 

 destrovs life and extinguishes combustion. Composition, 

 Sulphur 50-00, oxygen 50*00. 



Native Tellurium. 



Hexagonal; R/\R = 86° 57'. Occurs sometimes in 

 six-sided prisms with perfect lateral cleavage ; but is com- 

 monly granular massive. Color and streak tin-white. Brit- 

 tle. H. =2-2-5. G.=6-l-6-3. 



Sometimes contains a little iron, and also a trace of gold. 

 In an open tube, b.B. yields a white inodorous sublimate, 

 which may be fused to colorless transparent drops ; and on 

 charcoal fuses and volatilizes, tinging the flame green, and 

 covering the charcoal with white tellurium dioxide. 



Obs. Occurs in Hungary and Transylvania ; also, Boulder 

 Co., Colorado, at the Ked "Cloud Mine ; in Magnolia District 

 at the Keystone, Dun Eiver, and other mines ; in the Bal- 

 lerat District at Smuggler Mine ; in Central District at the 

 John Jay Mine, where masses of 25 pounds weight are re- 

 ported to have been found. 



Tellurium is also a constituent of ores of silver and lead (pp. 118, 149), 

 and these are the chief sources of the metal. 



Tellurite or Tellurous acid, Te0 2 , occurs at the Keystone, Smug- 

 gler, and John Jay Mines ; especially the last, where it is in minute 

 white or yellowish crystals having one eminent cleavage. 



Molybdenite. — Molybdenum Sulphide. 



_ Hexagonal. In hexagonal plates, or masses, thin foliated, 

 like graphite, and resembling that mineral. H. = 1-1 -5. 

 G. = 445-4-8. Color pure lead- gray ; streak the same, 



