Document 70Md6KXk5jjyRK6dZEd9GB1YE

"SERPENTINE Monoclinic. In distinct crystals, but only as pseudomorphs Sometimes foliated, folia rarely separable; also delicately fibrous, the fibers often easily separable, and either flexible or brittle. Usually massive, but micro scopically finely fibrous and felted, also fine granular to impalpable or cryptocrystalline; slaty* Crystalline in structure but often by compensation nearly Isotropic; amorphous* X-ray analysis of chrysotile shows that it is composed of bundles of parallel fibers, but although the Individual fibers are elongated parallel to one Crystallographic direction {c axis) their orientation otherwise varies* The structure israonoclinic* Pour molecules of H^MgaSis Oo in the unit cell. Each silicon atom is surrounded by four oxygen atoms aiJranged at the points of a tetrahedron, a part of the oxygen atoms being shared by neighboring.tetrahedral groups. Together these groups form chains extending parallel to the vertical axis. The chains are similar- to those of the amphiboles with the composition Tile binding forces between these chains are weak thus accounting for the fibrous structure. The arrangement of the Mg and OH groups is similar to that in brucite. Cleavage b(010), sometimes distinct; also prismatic (50) in chrysotile. Fracture usually conchoidal or splintery. Peel smooth, sometimes greasy. H. s 2.5-4* rarely 5* 5* G, = 2.50-2*65; some fibrous varieties 2 *2-2*5; retinalite, 2 *56-2 .55. Luster sub2>esinoU3 to greasy, pearly, earthy; resin-like, or wax-like; usually feeble* Color leek-greeh, blackish green; oil- and siskin-green; brownish red, brownish yellow; none bright; sometimes nearly white. On exposure, often becoming yellowish gray, streak white, slightly shining. Translucent to opaque. . E. FIBROUS. Chrysotile. Delicately fibrous, the fibers usually flexible and easily separating; luster silky, or silky metallic ; color greenish white, green, olive-green, yellow and brownish; 0. e 2*219. Often constitutes seams in serpentine. It includes most f the silky amianthus of serpentire rocks and much of what is popularly called asbestos fasbestus). Copied from - Dana, E. S. and W. E. Ford, A textbook of mineralogy. John Wiley, M. Y. 1+th. ed. 195-2, p. 674 "