jgo Elements of Mineralogy. 



part of that in ufe is prepared from the mar- 

 tial pyrites or mundic. 



Martial Pyrites is an iron ore containing 

 from -i to 1. of fulphur, from f to 4 of iron, 

 the remainder argill and filex, the three firft 

 intimately combined with each other, and 

 the iron in a femiphlogifticated ftate. Monnet 

 Eaux Miner. 281. 2 Gerh. Beytr. 57. It 

 ftrikes fire with fteel, and thence derives its 

 name; it is generally of a yellow or grey 

 colour, of a globular or cubic fhape, inter- 

 nally radiated and fometimes lamellar, com- 

 monly in part foluble in nitrous acid with 

 effervefcence, and flowly in the vitriolic, with 

 which it forms alum ; it detonnates flightly 

 with nitre and is very infufible : its fpecific 

 gravity is from 3,7 to 4,912, - Some pyrites 

 inftead of argillaceous contain calcareous 

 Earth, thefe are common in France, and in 

 them the iron is in a dephlogifticated ftate. 

 Monnet Mineral. 339. Pyrites are frequently 

 found in a ftatadtical fhape, and often form the 

 matter of petrifactions : they are alfo found 

 mixed and interfperfed through almoft every 

 other fpecies of ftone except granite. Accord- 

 ing to Mr. Monnet, thofe of a filamentous 

 or ftriated texture contain leaft fulphur, thofe 

 of a lamellar, moft ; the laft efflorefce diffi- 

 cultly if at all, and are faid to contain from 

 25 to 35 per cent of fulphur, 



Vitriol 



