(n.) A common mineral occurring in monoclinic crystals, with a prismatic angle of nearly 90, and also in massive forms which are often laminated. It varies in color from white to dark green and black, and includes many varieties differing in color and composition, as diopside, malacolite, salite, coccolite, augite, etc. They are all silicates of lime and magnesia with sometimes alumina and iron. Pyroxene is an essential constituent of many rocks, especially basic igneous rocks, as basalt, gabbro, etc.

amphibole antimony apatite aplite arsenic asbestos asphalt azurite bauxite billiard table bitumen boron bowling alley bowling green brimstone bromine brucite calcite carbon celestite chalcedony chalk chlorite chromite clay coal coke corundum cryolite diatomite driven snow emery epidote epsomite feldspar flat fleece flour foam garnet glass glauconite graphite gypsum hatchettine holosiderite ice iron pyrites ivory jet kyanite level lignite lily lime maggot magnesite mahogany malachite maltha marble marcasite marl meerschaum mica milk mineral coal mineral oil mineral salt mineral tallow mineral tar mineral wax molybdenite monazite obsidian olivine ozokerite paper pearl peat perlite phosphate rock phosphorus plane pumice pyrite pyrites pyroxene quartz realgar red clay rhodonite rock crystal rocks salt satin selenite selenium sheet siderite silica silicate silicon silk silver slide smooth snow spar spinel spodumene sulfur swan talc talcum tellurium tennis court velvet wollastonite wulfenite zeolite