One olive-colored variant of this mineral named prasiolite is typically produced by heat treatment of a more well-known variant. At high temperature, this mineral can undergo inversion, which converts its alpha variant to its beta variant. The hydrothermal process is used to artificially produce most industrial variants of this mineral (-5[1])since natural examples typically exhibit crystal twinning. “Deep Siberian” (10[1])and “Rose de France” are premier types of a purple variant of this mineral called amethyst. (10[1]-5[2])By (10[1])percentage, this mineral is the largest component of granite, and is the second most abundant mineral on earth after feldspars. For 10 points, name this mineral which is composed of silica. ■END■ (0[3])