462 NATURAL HISTORY. 



THIRD ORDER. 

 SCHWEFELKIES. IRON ORES COMBINED WITH SULPHUR. 



Schwefelkies Iron Pyrites Bisulphurct of Iron 

 the most widely spread of all the ores, occurs abundantly 

 in rocks of all ages, from the oldest crystalline to the most 

 recent alluvial deposits, either in the form of cubes or 

 crystals ; granular stalactitic masses, and often in irreg- 

 ular spheroidal nodules. Color bronze-yellow, gold, red, 

 or copper, running into brown veins, streaked brown or 

 black ; luster splendent metallic ; when broken or struck 

 sends forth a sulphurous odor, which is increased by 

 burning on charcoal. H. 6 to 5. G. = 4.9 to 5.1. 

 Found in veins or ore-beds in clay-slate, gray wacke ; in 

 short, all the primary rock formations, in every country, . 

 and strewn about in various localities. This species is 

 of high importance in the arts, although not affording 

 good iron ; heated, it gives off sulphur, and by a chem- 

 ical process yields sulphate of iron (green vitriol or 

 copperas), and sulphuric acid (oil of vitriol) of com- 

 merce, and also a considerable portion of sulphur and 

 alum. Iron pyrites were formerly used for striking fire, 

 instead of flints. 



Mispickel Arsenical Iron Pyrites occur in crys- 

 tals, prisms, massive or irregularly granular. Color 

 silver- white or steel-gray; luster shining and opaque. 

 Fused (or before the blow-pipe), affords arsenical fumes, 

 accompanied with a sulphurous odor. H. = 5.5 to 6. 

 G. = 6 to 6.2. Localities Freiburg. Altenberg, Sieben- 

 gebirge, and elsewhere in Europe ; Cornwall in Eng- 

 land, and in various places throughout the Eastern States. 

 Found mostly in primitive regions, and is commonly as- 



