ioz ■ FLINT GENUS. The mafiive occurs in coarfe and fine grained dif- tind concretions. Hard in a high degree yielding a little to the file.* Eafily frangible. j Intermediate between not particularly heavy, and ' heavy. Specific gravity — 3,464 to 3,556 Werner. _ 3,556 » 3,564, liauy.—3,5 to 3,576, Karjlen. Chemical Characters. Saxon topaz in a gentle heat turns white, ! but 3 ftrong heat deprives it of luftre and tranfparencf- the Brazilian, on the contrary, by expofure to a high temperature burns rofe red,} and in a ftill higb er ’ violet blue. Before the blow pipe it is fcarcely fnfi' ble, but expofed to a fleam of oxygen gas it f°° a melts into a porcellanous bead. It is fufible ^ 1 borax, but alkali has little effed on it. Phyfical Characters. The topaz of Brazil, Siberia, and Mucla in ^ < ftlinor, when heated exhibit at one extremity p 0 ^ five, and the other negative eledricity. The SaX° n ’ by fridion, gives figns 6f eledriciiy. * It,cuts quartz, but is cut by ruby Ha’/y. -}- When thus altered ■the Saxon topaz is fometimes loW diaip.ond. ,, '! 1 tB } Topaz thus altered is cut and fold by jewellers un<l° Bjtjne of Brazilian ruby and pale fpinelle. . ConsU^ 0 ’
