Jasper
Like carnelian, agate, and chalcedony, this mineral is chiefly composed of silex, but it always contains more iron, and hence, instead of being translucent, like them, it is always opaque. Its colors are red, yellow, and brown; specific gravity 2.70. Its composition is silex 75, alumina 0.5, lime 0.02, iron 13. It is infusible. See PRECIOUS STONES.