Nephrite - Definition and Overview

There is also a community named Actinolite,_Ontario in Canada.

Well-cleaved, dark, fine-grained chlorite-actinolite metadiabase intrudes light granitic gneiss

Actinolite is an inosilicate mineral with the chemical formula
Ca₂(MgFe)₅Si₈O₂₂(OH)₂

Mineralogy

Actinolite is an intermediate member in a series between tremolite (Mg-rich) and ferro-actinolite (Fe-rich). As seen from the chemical formula above, Mg and Fe ions can be freely exchanged in the crystal structure.

Occurrence

Actinolite is commonly found in metamorphic rocks, such as contact aureoles surrounding cooled intrusive igneous rocks. It is also occurs as a product of metamorphism of magnesium-rich limestones.

Some forms of asbestos are formed from fibrous actinolite, the fibres being so small that they can enter the lungs and damage the alveoli. Another form of actinolite, known as nephrite, is one of the two common constituents of jade (the other being jadeite).

Details

Related minerals

1. Tremolite
2. Jade

Reference

• Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., John Wiley and Sons, New York ISBN 0471805807