Actinolite

A green amphibole forming radiating sprays of long crystals in greenschist rocks.

Actinolite specimen — Photo: Didier Descouens, CC BY-SA 4.0, via Wikimedia Commons

How to identify actinolite

Bright to dark green needles or blades.
Often radiating like a star.
Two amphibole cleavages.

Often confused with

Epidote
Epidote is a yellowish pistachio green with one cleavage.
Compare side by side
Tremolite
Tremolite is white to gray.
Compare side by side

Where it's found

Zillertal, Austria
Vermont
Switzerland

Uses

Collector specimens; fine-fibered actinolite forms nephrite jade.

Rock tumbling

Can be tumbled with care.

Did you know?

Its name comes from Greek aktis, 'ray', for its radiating crystals.

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