Dictionary:

tremolite

  (trĕm'ə-līt')

A white to dark gray amphibole mineral, Ca₂Mg₅Si₈O₂₂(OH)₂, typically occurring in aggregates and used as a substitute for asbestos and in paints and ceramics.

[French trémolite, after Tremola, a valley in the Swiss Alps.]

The name given to magnesium-rich monoclinic calcium amphibole Ca₂Mg₅Si₈O₂₂(OH)₂ The mineral is white to gray, but colorless in thin section. Unlike other end-member compositions of the calcium amphibole group, very pure tremolite is found in nature. Substitution of Fe for Mg is common, but pure ferrotremolite, Ca₂Fe₅Si₈O₂₂(OH)₂ is rare. Intermediate compositions between tremolite and ferrotremolite are referred to as actinolites, and are green in color and encompass a large number of naturally occurring calcium amphiboles. See also Amphibole.

The noun has one meaning:

Meaning #1: a white or pale green mineral (calcium magnesium silicate) of the amphibole group used as a form of asbestos

A sample of tremolite

Tremolite is a member of the amphibole group of silicate minerals with composition: Ca₂Mg₅Si₈O₂₂(OH)₂. Tremolite forms by metamorphism of sediments rich in dolomite and quartz. Tremolite forms a series with actinolite and ferro-actinolite. Pure magnesium tremolite is creamy white, but the color grades to dark green with increasing iron content. It has a hardness on Mohs' scale of 5 to 6.

A fibrous variety of tremolite is used as asbestos. This material is toxic and inhaling the fibers can lead to asbestosis, lung cancer and mesothelioma. One of the two minerals of the gemstone jade is nephrite, a green variety of tremolite.

Tremolite is an indicator of metamorphic grade since at high temperatures it converts to diopside. Calcite, grossular, talc, and serpentine are common associates of tremolite.

References

• Webmineral
• Mindat
• Mineral galleries
• Mineral may unlock secrets of Venus's ancient oceans, New Scientist, 10 October 2007

See also

• Libby, Montana

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