Page:Theophrastus - History of Stones - Hill (1774).djvu/287



HE Stone is of a peculiar Genus, differing both from Crytal and Spar; and demands a ditinct Place and Name; as well from its natural Character, as for its artificial Products: It has been called Fluor, Spatum vitrecens, and Flus. It is heavy, unctuous, oft, emi-tranparent, and gloy: It breaks in a rudely plated Form; not rhombic.

We find it in large Maes; or Cluters of maller Lumps; in ome Degree reembling Spar, and of the like gloy Surface; but without the peculiar Form, or real Characters of that Stone.

A Knife will cratch it: It does not readily ferment with Acids, nor will it trike Fire with Steel: It neither burns to Glas, nor Lime; but expoed to the Action of a violent Fire, it plits into thin, irregular, flaky Fragments, and by Degrees crumbles into a Kind of Powder, over which the Fire has no farther Power. The Fragments do not this Way burn to Lime, nor can a calcareous Subtance be any way extracted from them: But tho' no Fire will vitrify it alone, yet mixed with a calcareous Earth we ee it pe culiruns freely into a Glas. And that it is of a peculiar