GUIDE TO THE MINER A LOGIC COLLECTIONS 



S3 



Stephanite (brittle silver ore) Ag D SbS 4 



Stephanite is a stilfantimbnite of silver containing 16.3$ sul- 

 fur, L5.2$ antimony and 68.5$ silver. 



Orthorhomibic crystals in short prismatic and tabular forms 

 arc frequently found. The mineral usually occurs in fine grained 

 masses of an iron-black color and metallic luster. Also in dis- 

 seminated grains. 



Stephanite occurs in veins with other silver ores, the principal 

 Localities being those mentioned under argentite, pyrargvi i1 e, 

 etc. 



Enargite Cu. ; AsS 4 



Enargite is a sulfarsenite of copper containing 32.6$ sulfur, 

 19.1$ arsenic and 48.3$ copper. 



Orthorhombic crystals arc sometimes met with; these are pris 

 matic in habit and striated parallel to the vertical axis. Enar- 

 gite commonly occurs in columnar or granular masses. It is 

 black in color and has a metallic luster. 



Enargite is found associated with other copper minerals in 

 Chile, Peru and Mexico; also in South Carolina, Colorado, Utah, 

 California and in the Tintic district of Montana. 



It is an ore of copper. 



HALOIDS 



CIILORIDS, BROMIDS, IODIDS, FLUORIDS 



Halite (rock salt) NaCl 



Halite or common salt is the chlorid of sodium and contains 

 39.4$ chlorin and 60.6$ sodium. It seldom occurs perfectly pure 

 but is commonly mixed with calcium sul- ! *~== ==== 



fate, calcium chlorid, magnesium chlorid 

 and magnesium sulfate. 



Halite is isometric and usually crystallizes 

 in cubes (pi. 17 2 ), which often show distortion 

 and cavernous faces, as in rig. 176. Masses 



with perfect cubic cleavage are common as Fjg m 



well as a fibrous variety which is said to be Hante 

 pseudomorphous after fibrous gypsum. Halite has a vitreous 

 luster and when pure is colorless and transparent; yellow, red, 

 brown, blue and purple shades are due to impurities, as is also 

 the translucency accompanying these variations in color. It has 

 a characteristic saline taste. 



