tremolite


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tremolite:

see amphiboleamphibole
, any of a group of widely distributed rock-forming minerals, magnesium-iron silicates, often with traces of calcium, aluminum, sodium, titanium, and other elements.
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Tremolite

 

(named for the Tremola Valley in the southern Swiss Alps), a monoclinic amphibole, Ca2Mg5[Si4O11](OH,F)2. Admixtures of Na, Fe, Mn, and Cr are regularly distributed in the octahedral positions of the structure, and admixtures of Al and P are located in the tetrahedral positions. The F~ and OH” content is correlated with the temperature of formation; tremo-lite with increased concentrations of F serves as a geologic thermometer for the characteristics of high-temperature geologic processes.

Tremolite forms grayish white acicular crystals and radiating columnar aggregates. Compact cryptocrystalline tremolite deposits are called nephrite, and silky fibrous aggregates form mountain leather or mountain cork. The hardness of tremolite on Mohs’ scale is 6–6.5, and its density is about 3,000 kg/m3.

Tremolite is a typical metamorphic mineral, formed in the early stage of contact metamorphosis of dolomites and lime stones. It is also characteristic of a low degree of regional metamorphism; it occurs less frequently in alpine-type veins and pegmatites. Deposits of mountain leather are located in Italy (Lombardy) and on Corsica.

tremolite

[′trem·ə‚līt]
(mineralogy)
Ca2Mg5Si8O22(OH)2 Magnesium-rich monoclinic calcium amphibole that forms one end member of a group of solid-solution series with iron, sodium, and aluminum; occurs in long blade-shaped or short stout prismatic crystals and also in masses or compound aggregates.
References in periodicals archive ?
2012b) using samples of chrysotile asbestos sediments from a slow-moving landslide on Sumas Mountain, Washington, and from naturally occurring tremolite in El Dorado Hills, California--both areas are of concern due to exposures to local communities.
Quartzites and tremolite schist are the most common lithologies near the contact with the Parashi Stock and commonly appear in interlayered white and black millimetrical bands (MO-2IVD-5).
Any underestimation of the activity of tremolite will lower the temperatures determined using both of the equilibria.
The government claims that the defendants, beginning in the late 1970s, obtained knowledge of the toxic nature of tremolite asbestos in its vermiculite through internal epidemiological, medical and toxicological studies, as well as through product testing.
While all variants of asbestos are crystalline in nature, the needles of tremolite are especially long and sharp.
The talcs are said to be tremolite (asbestos)free and the calcium carbonates free of crystalline silica.
Asbestos-related pleural disease due to tremolite associated with progressive loss of lung function: Serial observation in 123 miners, family members, and residents of Libby, Montana.
The sources of these noncommercial amphiboles varied and included tremolite contamination of chrysotile (cases 1 and 4, Table 3), tremolite and actinolite contamination of vermiculite (case 5, Table 3), environmental exposure to tremolite and actinolite (case 2, Table 3), and exposure to anthophyllite during the manufacture of cement pipes (case 3, Table 3).
Thin section study reveals that the amphiboles are mainly hornblende, tremolite and chlorite.
Gangue minerais consist of quartz, sericite, chlorite, actinolite, tremolite, hornblende and calcite (Minfile 103P 023).