ORDER*. PRISMATIC IRON-PYRITES. 



Iron-pyrites and rhombahedral Quartz, by several Lime- 

 haloides, and other species, and it is often an important in- 

 gredient of those beds which contain ores of lead, iron, &c. 

 It is frequently mixed with coal seams and the beds of 

 clay which occur along with them. Here it is generally 

 accompanied by the prismatic Iron-pyrites. In veins, 

 where it is likewise met with in considerable quantities, 

 its principal associates are dodecahedral Garnet-blend? 1 , 

 prismatic Arsenical-pyrites, hexahedral Lead-glance, and 

 pyramidal Copper-pyrites. The auriferous Pyrites contain 

 a small portion of hexahedral Gold mechanically mixed up 

 with them. Hexahedral 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 spe- 

 cies which can be distinctly traced in the composition of 

 some of the meteoric masses. 



4. It would far exceed the limits of the present work tb 

 mention more than those localities where particularly re- 

 markable varieties have been found. Some of the crystals, 

 along with their localities, have been mentioned above. 

 The island of Elba is the most conspicuous for large and 

 well defined crystals ; very fine crystals are found in Pied- 

 mont, and many other interesting crystallised varieties 

 at Freiberg, Johanngeorgenstadt, &c. in Saxony, ia Bohe- 

 mia, in Hungary, in the Hartz, at Kongsberg in Norway, 

 at Fuhlun in Sweden, in Derbyshire and Cornwall, and 

 in many other countries in and out of Europe. 



5. Hexahedral Iron-pyrites is roasted for extracting sul- 

 phur; afterwards having been exposed to the oxidating in- 

 fluence of the atmosphere, it yields sulphate of iron and 

 sulphuric acid. The remaining oxide of iron is used as a 

 coarse pigment. It is an important agent in several metal- 

 lurgical operations. Formerly it used to be employed in- 

 stead of flint in gun-locks. 



2. PUISMATIC IRON-PYRITES. 

 Prismatic Iron-Pyrites. JAM. Syst. Vol. III. p. 29y. Man, 



