GRANITE, a compound rock, constituting the lowest of the geological formations, according to older geologists; but it has lately been found resting even on secondary formations in the Alps. It (essentially) consists of quartz, felspar, and mica. Its great durability as a material for building is attested by many of the ancient Egyptian monuments, in which the stone exhibits no appearance of decay even after a lapse of 3000 years. There are some granites, however, which shake and crumble down in a very few years, particularly those in which felspar predominates. This rock becomes refractory to work after it has been some time quarried; and it is usual to keep it for some time under water before it is wrought into ornamental objects. See MINERALOGY and GEOLOGY.