is a member of the amphibole
group of silicate minerals
with composition: Ca2Mg5Si8O22
. Tremolite forms by metamorphism
of sediments rich in dolomite
. Tremolite forms a series with 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.