38 The BEDS 



CHAP. IV. 



Of the Beds of the Pyrites. 



TH E yellowifh or fulphur pyrites is met with 

 in all manner of (tone : i. in quartz or flint 

 it readily lodges •, this very clofe, firm itone ge- 

 nerally affording beds, and directing to ores, that 

 when once difcovered, the Miner imagines himfelf 

 to be, if not in the actual pofieffion, yet in the 

 tolerably certain hope of meeting with an ore •, it 

 alfo forms the felvdges* of Veins, and cncompafTes 

 the pyrites as fo many fhells or coats. The pyrites 

 often adheres externally to quartz, as if run or 

 melted upon it, or fticks like grains or buttons, 

 or like fand ftrewed on it ; as is particularly ob- 

 fervable in the beautiful colours of the copper- 

 pyrites. 



2. In Marbles, called in the language of Miners, 

 horn-ftcne 7 and refembling quartz; except that 

 the former are generally white, feamy, veiny and 

 fiakey •, the latter for the moil part coloured, 

 as brown, yellow, red, grey, black, &c. and more- 

 over are not fo remarkably veiny, but clofcr and 

 confequently fitter to work. I have more efpecially 

 obferved the pyrites on red and yellow jafper, 

 chalcedon, and the like, which are not unduly 

 claffed amongil marbles. 



3. In 



* A vein has its bed and cover of rock, both which are 

 parced or difcontinued on the fides of a vein, and thefe fides 

 covered with quartz, or with a finer kind of mold \ and this is 

 what Miners call ikeftfoagti. 



