Search results
Results from the WOW.Com Content Network
Three polytypes of chrysotile are known. [8] These are very difficult to distinguish in hand specimens, and polarized light microscopy [6] must normally be used. Some older publications refer to chrysotile as a group of minerals—the three polytypes listed below, and sometimes pecoraite as well—but the 2006 recommendations of the International Mineralogical Association prefer to treat it as ...
Amosite and crocidolite are considered the most hazardous asbestos fiber types; [5] however, chrysotile asbestos has also produced tumors in animals and is a recognized cause of asbestosis and malignant mesothelioma in humans, [6] and mesothelioma has been observed in people who were occupationally exposed to chrysotile, family members of the ...
The most common asbestiform mineral is chrysotile, commonly called "white asbestos", a magnesium phyllosilicate part of the serpentine group. Other asbestiform minerals include riebeckite, an amphibole whose fibrous form is known as crocidolite or "blue asbestos", and brown asbestos, a cummingtonite-grunerite solid solution series.
Pleural contamination with asbestos or other mineral fibers has been shown to cause cancer. Long thin asbestos fibers (blue asbestos, amphibole fibers) are more potent carcinogens than "feathery fibers" (chrysotile or white asbestos fibers). [28] However, there is now evidence that smaller particles may be more dangerous than the larger fibers.
Diopside is a precursor of chrysotile (white asbestos) by hydrothermal alteration and magmatic differentiation; [6] it can react with hydrous solutions of magnesium and chlorine to yield chrysotile by heating at 600 °C for three days. [7]
In contrast, lizardite and chrysotile typically form near the Earth's surface and break down at relatively low temperatures, probably well below 400 °C (800 °F). It has been suggested that chrysotile is never stable relative to either of the other two serpentine polymorphs.
In the late 19th century and early 20th century, asbestos was considered an ideal material for use in the construction industry. It was known to be an excellent fire retardant, to have high electrical resistance, and was inexpensive and easy to use.
More precisely, serpentine soil contains minerals of the serpentine subgroup, especially antigorite, lizardite, and chrysotile or white asbestos, all of which are commonly found in ultramafic rocks. The term "serpentine" is commonly used to refer to both the soil type and the mineral group which forms its parent materials.