A sample of tremolite (unknown scale)

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. Nephrite, one of the two minerals of the gemstone jade, is a green variety of tremolite.

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.

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.

[edit] See also

• Libby, Montana – location of asbestos-related ailments caused by tremolite

[edit] References

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