Pyroxene n. (Min.) 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. Note: The pyroxene group contains pyroxene proper, also the related orthorhombic species, enstatite, bronzite, hypersthene, and various monoclinic and triclinic species, as rhodonite, etc.
... origin. The rocks named trachytes by M. Hauey merit the same attention. They are distinguished above all by primitive porphyries, intermediate or secondary, by the absence of quartz and the presence of pyroxene or ... — Movement of the International Literary Exchanges, between France and North America from January 1845 to May, 1846 • Various Read full book for free!
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