A variety of actinolite, nephrite , is one of the two minerals called jade . The other jade mineral is jadeite . Although nephrite is considered to be actinolite, the lighter shades of nephrite probably contain significant amounts of tremolite. The tremolite fibers form a felted mass that has all the appearances and feel of a piece of cloth. The mountain leather will even have attached calcite crystals that seem to be knitted in to the fabric.
Tremolite is an important temperature indicator for petrologists.
CaMgSi 2 O 6 . The presence of only tremolite and no diopside indicates that the rock has not endured terribly high temperatures. Tremolite can be a fun and very interesting mineral to collect. Color is usually white or gray but can be greenish, colorless, yellow and violet. Luster is vitreous or silky to dull.