tremoliet

Tremolite is a common mineral species of the tremolite-actinolite group, with the chemical formula Ca2(Mg,Fe)5Si8O22(OH)2. It is a green to yellowish-green, fibrous, and massive mineral that forms in metamorphic rocks, typically in the presence of carbonaceous material. Tremolite is a member of the amphibole group, which also includes actinolite, hornblende, and anthophyllite.

The name "tremolite" is derived from the Latin word "tremulus," meaning trembling, in reference to the mineral's tendency to split into thin, flexible fibers. These fibers are often used in asbestos products, although tremolite itself is not considered a harmful form of asbestos. Tremolite is typically found in schist, gneiss, and other metamorphic rocks, often associated with serpentine and talc.

Tremolite exhibits a vitreous to pearly luster and a white streak. It has a specific gravity of approximately 3.2 and a Mohs hardness of 5 to 6. The mineral's cleavage is perfect on {100} and good on {010}, and it has a conchoidal fracture. Tremolite is biaxial with a positive optic sign, and its refractive indices are nω = 1.630-1.640, nε = 1.650-1.660.

Tremolite is not typically used in jewelry due to its fibrous nature and the potential for asbestos-like properties. However, it is sometimes used in mineral collections and as a decorative stone in some cultures. The mineral is also of interest to mineralogists and geologists for its role in understanding metamorphic processes and the formation of metamorphic rocks.