Flint Or Silex ( silica is the appellation of the simple earth). Is commonly of a gray colour, varying from ash gray to grayish black and brownish red ; it occurs generally in roundish masses of no great magnitude, rarely in crystals, and sometimes in hollow or perforated globules. It is found in almost all countries, although not very abundantly in Scotland, and is used when split into narrow thin pieces, as flints for gun-locks, or to strike fire with steel to light matches, and for the manufacture of glass instead of fine sand. According to Klaproth, flint contains 98 silica, lime 050, alumina 025, oxide of iron 0 25, and loss 1 = 100. The best flints are found in the chalk or lime quarries. The Indians use two pieces of wood, which they rub violently against each other, instead of steel and flint, to generate fire or inflame a match.