426 • DIAMOND GENUS. Davoifier, Tennant, Lampadins, and Morveau, have demonftrated that it is nearly pure carbone. ^ Chemical Characters. Begins to burn at a temperature not exceeding 14° or 15° of Wedgev/ood Phyfical Characters. It ffiews figns ofpofitive electricity by rubbing; and it is faid to ffiine in the dark, after having been ex*, pofed for fome time to the rays of the fun. This lat-^ ter property is denied by Werner, who affirms that he repeatedly made the experiment, but without fuc*! cefs. Geognostic Situation. It is found fometimes loofe in fand, fometimcs in* clofed in a loamy earth. Its original repofitot/ (lagentdtie) is dill imperfectly known. Werner’ fufpefts that it occurs, like hyacinth, zircon, pyrop c and ipinelle, imbedded in rocks belonging to the newed llcetz trap formation. * Klcholfoa’s Journal, v, 134.