Serpentine-asbestos Chrysotile

PHYSICAL PROPERTIES a group of six different minerals occurring naturally in the environment most common type is white others are blue, gray, or brown long thin fibers similar to fiberglass not volatile not soluble serpentine asbestos chrysotile mineral, strong, resistant to chemicals and heat amphibole asbestos brittle fibers, resistant to chemicals and heat... 

UICC standard amphi-bole asbestos amosite and crocidolite, UICC serpentine asbestos chrysotile A (Rhodesian), Oregon erionite, glass wool, rock wool... 

Chrysotile A mineral in the serpentine group composed of hydrated magnesium silicate, which occurs in several crystalline modifications (see chapter 2) and usually in fibrous form. First described and named in 1834, chrysotile fibers were mined under the name serpentine-asbestos, or simply asbestos, long before that time. 

Serpentine-asbestos An early name for the fibrous form of serpentine rock that was mined. Today the term refers to chrysotile-asbestos. 

Deer, Howie and Zussman (19J give physical and optical constants for amphibole minerals in Vol. two, Rock Forming Minerals, (chain silicates), and for Serpentine minerals (chrysotile) in volume three (sheet silicates). X-ray diffraction data is obtainable from the Powder Diffraction file, Inorganic (20). This data can be used for a double check of asbestos standards. 

Economically important metamorphic minerals such as serpentine can affect health. In the past few years, asbestos removal has had significant impact on the cost of operating schools and other public buildings, hi the confusion over illness associated with asbestos made from the amphibole mineral crocidolite, citizens demanded the removal of all asbestos, unaware that a less-hazardous form of asbestos, the serpentine mineral chrysotile, also was removed at great expense. 

Double-chain silicates, shown in Figure I5.13f, find some SiO units sharing two oxygens while others share three. The repeating unit is Si40if. Five double-chain silicates [tremolite, anthophyllite, actinolite, amosite ( brown asbestos ), crocidolite ( blue asbestos ), all members of the amphibole family of minerals] and the serpentine mineral chrysotile ( white asbestos ) are classified under the generic name asbestos. The molecular-level chain structure of these materials is reflected in... 

Mica group Biotite Lepidohte Muscovite Paragonite Phlogopite. Serpentine group Antigorite Asbestos Chrysotile Clinochry-sotile Lizardite Orthochrysotile Parachrysotile. 

A second class of silicate mineral called asbestos is a serpentine mineral, chrysotile. It is a magnesium silicate hydrate, Mg6[Si40n(0H)6]H20, with a chemical composition similar to talc, Mg3Si40io(OH)2. There is at least a plausible argument that chrysotile should not have been included with other minerals named asbestos from chemical, health, and legal considerations. There is small doubt that the amphiboles are much more likely to cause difficulties. A study of two cement pipe plants in New Orleans revealed some interesting results. In one... 

Chrysotile (serpentine) occurs in both clino and ortho stmctures. Both one-layer ortho and clino, and six-layer ortho (as in nacrite) stmctures have been observed. Chrysotile transforms at high temperature to forsterite [15118-03-3] and siHca. Particularly fibrous varieties are called asbestos (qv). 

Serpentine An asbestos mineral with a wav-y appearance, such as chrysotile. 

The most important of these groups is the serpentine mineral group, because it includes the fibrous mineral species chrysotile, which is the most common fibrous mineral and the one most widely mined, processed, and manufactured as asbestos. 

Fig. 2.4 Chrysotile asbestos sectioned perpendicular to the fiber axis. Electron micrograph showing typical lattice images of the layers of this serpentine mineral rolled into hollow cylinders (fibrils).

ASBESTOS. The tenn asbestos is a generic designation referring usually to six types of naturally occurring mineral fibers which are or have been commercially exploited, These fibers are extracted from certain varieties of hydrated alkaline silicate minerals comprising two families seipe.ntin.es and amphiboles. The serpentine group contains a single fibrous variety chrysotile five fibrous forms of amphiboles are known anthophyllite, amosite, crocidolite. tremolite, and actinolite... 

CHRYSOTILE. A delicately llbrous variety of serpentine which separates easily into silky, flexible fibers of greenish or yellowish color, wrlh formula MgtSUOdGHlj. It crystallizes m the monoclinic system hardness. 2.5 sp gr, 2.55. Its name is derived from [he Greek words meaning gold and fibrous. Most of the common asbestos of commerce is chrysolile. It is mined in Thelford. Province of Quebec, and in the Republic of South Africa. See also Asbestos and Serpentine. 

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