PYRITES (FeS 2) in the form of small crystals and specks of a brassy-yellow colour may be found frequently in quartz. Four pieces of Brazilian quartz, containing pyrites inclusions, have now been ...

IN NATURE, vol. xi. p. 249, Mr. Carr mentions the fact that some iron pyrites in the Maidstone Museum “have crumbled into a coarse, finely divided mass;” and he inquires whether “such a thing has ever ...