Actinolite

Real mineral · common · Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂

Calcium magnesium iron amphibole forming in low to medium grade metamorphic rocks. The massive nephrite jade variety is one of the two minerals sold as jade. Fibrous actinolite is a recognised asbestos mineral.

Identity

Formula

Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂

Chemical class

silicate

Mineral group

Hornblende, Richterite, Tremolite

Also known as

Nephrite jade (massive variety), Byssolite (fibrous)

Crystallography

Crystal system

monoclinic

Habits

prismatic, bladed, fibrous, massive

Fracture

subconchoidal

Physical properties

Mohs hardness

5.5

Density

3.04 g/cm³

Luster

vitreous, silky

Colors

green, dark green, gray-green, black

Streak

white

Transparency

transparent, translucent

Geology

Origins

metamorphic

Host rocks

schist, phyllite, marble

Associated minerals

Tremolite, Chlorite, Epidote, Albite

Geography

Canada, New Zealand, Taiwan, China, Russia

Classification

Rarity

common

Gem quality

No

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