PHYSIOGRAPHY. 285 



Iron Pyrites. 



Imbedded and implanted globules ; surface drusy ; com- 

 position indistinctly columnar. Massive ; composition gran- 

 ular, sometimes even impalpable, strongly coherent; frac- 

 ture uneven, or on a large scale, flat conchoidal. Cellular. 



1. In the oxidating flame of the blow-pipe, Iron Pyrites becomes red 

 upon charcoal, the sulphur is expelled, and oxide of iron remains. At a 

 high temperature, in the interior flame, it melts into a globule, which 

 continues red-hot for a short time when removed from the blast, and pos- 

 sesses, after cooling, a crystalline fracture and metallic appearance. In 

 heated nitric acid, it is partly soluble, and leaves a whitish re&idue. Some 

 varieties are subject to decomposition when exposed to the action of the 

 atmosphere. 



2. Analysis. 

 By HATCHETT. 



Iron - * 47-30 - - 47-85 



Sulphur - 52-70 - - 52-15 



3. Iron-Pyrites is one of the most common and widely diffused species 

 among the ores ; and occurs in very various repositories. It is engaged 

 in imbedded crystals, and in massive nodules ; the former particularly in 

 clay-slate and greywacke-slate, the latter in greenstone, granular lime- 

 stone, &c. It even forms beds by itself, included in primitive slate ; and 

 is often an important ingredient of those beds which contain ores of lead, 

 iron, &c. It frequently occurs mixed with coal seams, and the beds of 

 clay which form a part of the ccal measures. The Auriferous Pyrites 

 contains a small portion of native gold mechanically mixed with it, 

 which appears to operate by a galvanic effect in producing the decompo- 

 sition to which this variety is so generally subject. Iron- Pyrites is also 

 found with ores of silver. It is contained in many organic remains, both 

 of vegetable and animal origin, and is one of the species which can be 

 distinctly traced in the composition of some of the meteoric masses. 



4. Some of the crystals, along with their localities, have been men- 

 tioned above. The island of Elba is the most conspicuous for large and 

 well defined crystals : very fine crystals are found in Piedmont, at Frei- 

 berg, Johanngeorgenstadt, &c. in Saxony, in Bohemia, in Hungary, in 

 the Hartz, at Kongsberg in Norway, at Fahlun in Sweden, in Derby- 

 shire and Cornwall. 



The United States is not particularly rich in localities of interesting 

 varieties of Iron-Pyrites. Shoreham, (Vt.) and Schoharie, (N. Y.) pro? 



