A green mineral of the amphibole group containing calcium, magnesium, and iron and occurring chiefly in metamorphic rocks and as a form of asbestos.
More example sentences
- They have a mineralogical association of quartz, diopside, actinolite, plagioclase and K-feldspar.
- Amosite, fibrous anthophyllite, fibrous tremolite, fibrous actinolite, and crocidolite are amphiboles, double-chain silicates, which observed microscopically look like sharp needles.
- Kyanite, microcline, zircon, monazite and opaque minerals are variably present with epidote, actinolite and chlorite being present as secondary alteration minerals.
late 18th century: from Greek aktis, aktin- 'ray' + lithos 'stone' (because of the ray-like crystals).