ikon. 173 



figs. 2 to 7 ; also figs. 8 to 15 on page 6. Fig. 6, a pentag- 

 onal dodecahedron, is a common form. Occurs also in imi- 

 tative shapes, and massive. 



Color brass-yellow ; streak brownish black. Lustre of 

 crystals often splendent metallic. Brittle. H. = 6-6*5, be- 

 ing hard enough to strike fire with steel. G. =4 , 8-5*l. 



Composition. Fe S 2 = Sulphur 53*3, iron 46*7 = IOC. 

 B.B. on charcoal gives off sulphur, and ultimately affords 

 a globule attractable by the magnet. 



Pyrite often contains a minute quantity of gold, and 

 is then called auriferous pyrite. See under Gold. Nickel, 

 cobalt and copper occur in some pyrite. 



Diff. Distinguished from copper pyrites in being too hard 

 to be cut by a knife, and also in its paler color. The ores 

 of silver, at all resembling pyrite, instead of having its pale 

 bronze-yellow color, are steel-gray or nearly black ; and be- 

 sides, they are easily scratched with a knife and quite fusible. 

 Gold is sectile and malleable. 



Obs. Pyrite is one of the most common ores on the 

 globe. It occurs in rocks of all ages. Cornwall, Elba, 

 Piedmont, Sweden, Brazil, and Peru, have afforded magnifi- 

 cent crystals. Alston Moor, Derbyshire, Kongsberg in Nor- 

 way, are well-known localities. It has also been observed in 

 the Vesuvian lavas, and in many other igneous rocks. 



In the United States, the localities are numerous. Fine 

 crystals have been met with at Rossie, N. Y. ; at many 

 other places in that State ; also in each of the New England 

 States and in Canada ; in New Jersey, Pennsylvania, Vir- 

 ginia, North Carolina, Georgia, in Colorado, Wyoming and 

 the States west. It occurs in all gold regions, and is one 

 source of gold. 



This species is of the highest importance in the arts, 

 although not affording good iron on account of the diffi- 

 culty of separating entirely the sulphur. It affords the 

 greater part of the sulphate of iron (green vitriol or copperas) 

 and sulphuric acid (oil of vitriol) of commerce, and also 

 a considerable portion of the sulphur and alum. To make 

 the sulphate the pyrites is sometimes heated in ciay retorts, 

 by which about 17 per cent, of sulphur is distilled over and 

 collected. The ore is then thrown out into heaps, exposed 

 to the atmosphere, when a change ensues by which the re- 

 maining sulphur and iron become through oxidation sul- 

 phate of iron. The material is lixiviated, and partially eva- 



