4G4 NATURAL HISTORY. 



malachite and heavy spar. Massive varieties are found 

 at the New Jersey mines, and in Pennsylvania. 



Copper Glance Vitreous Copper Ore. Seldom 

 plainly crystallized, mostly of massive structure, granu- 

 lar or compact, and disseminate. Color lead-gray, some- 

 times streaked ; luster shining metallic, streak blackish ; 

 opaque. H. = 2.5 to 3.0. G. 5.4 to 5.7. Heated, 

 gives off fumes of burning sulphur. Occurs associ- 

 ated with the above described, and is used for the same 

 purposes. 



Silver Glance Vitreous Silver Sulphuret of Sil- 

 ver occurs in various forms, as crystals, simple and com- 

 pound ; reticulated, filiform, arborescent ; also massive. 

 Color lead-gray, often brown and black, varied or veined ; 

 luster metallic, shining, flexible, opaque ; streak black ; 

 intumesces by heat, and gives off a sulphurous odor. H. 

 = 2 to 2.5. G-. = 6.8 to 7.1. Localities Mexico, Chili, 

 Peru, Chemnitz, Hungary, etc., and in the mining re- 

 gions of the Schneeberg and Hartz in Germany. It is a 

 common ore in the mines of Mexico and South Amer- 

 ica ; a mass of sulphuret of silver is said to have been 

 found at Sparta, Tennessee. "Occurs also with native 

 silver and copper in Northern Michigan; considered a 

 highly valuable ore. 



Lead Glance Galena Sulphuret of Lead occurs 

 mostly in crystals, but also in globules, reticulated, tab- 

 ular and massive ; color lead-gray, sometimes iridescent. 

 Luster metallic; streak, dark gray; opaque. Decrepi- 

 tates by burning, unless heated with caution, and mostly 

 contains a portion of silver. II. 2.5. G. = 7.5 to 

 7.7. Galena is found everywhere, from the primary 

 rock formation to the Lias system: associated with ores 

 of zinc, silver, and copper. The deposits of this ore in 



