Actinolite

Actinolite is an amphibole silicate mineral. The name derived from the Greek word aktis, meaning “beam” or “ray”, because of the mineral’s fibrous nature. Commonly found in metamorphic rocks, such as contact aureoles surrounding cooled intrusive igneous rocks. It also occurs as a product of metamorphism of magnesium-rich limestones.

Some forms used as gemstones. One is nephrite, one of the two types of jade (the other being jadeite, a variety of pyroxene). Another gem variety is the chatoyant form known as cat’s-eye actinolite. This stone is translucent to opaque, and green to yellowish green color. This variety has had the misnomer jade cat’s-eye. Transparent actinolite is rare and faceted for gem collectors.