actinolite

American  

[ak-tin-l-ahyt, ak-tuh-nl-] / ækˈtɪn lˌaɪt, ˈæk tə nl- /

noun

Mineralogy.

1. a variety of amphibole, occurring in greenish bladed crystals or in masses.

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actinolite British  

/ ækˈtɪnəˌlaɪt /

noun

1. a green mineral of the amphibole group consisting of calcium magnesium iron silicate. Formula: Ca 2 (Mg,Fe) 5 Si 8 O 22 (OH) 2

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actinolite Scientific  

/ ăk-tĭn′ə-līt′ /

1. A greenish variety of amphibole. Actinolite is a monoclinic mineral, and occurs in long, slender, green needlelike crystals, or in fibrous, radiated forms in metamorphic rocks. Chemical formula: Ca ₂ (Mg,Fe) ₅ Si ₈ O ₂₂ OH ₂ .

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Other Word Forms

• actinolitic adjective

Etymology

Origin of actinolite

First recorded in 1825–35; actino- + -lite

Example Sentences

One internal document from 1973 allegedly says: "Our baby powder contains talc fragments classifiable as fiber. Occasionally sub-trace quantities of tremolite or actinolite are identifiable…"

From BBC • Oct. 15, 2025

J&J didn’t tell the FDA about a 1974 test by a professor at Dartmouth College in New Hampshire that turned up asbestos in talc from J&J – “fiberform” actinolite, as he put it.

From Reuters • Dec. 14, 2018

That’s one of six minerals – along with chrysotile, actinolite, amosite, anthophyllite and crocidolite – that occur in nature as crystalline fibers known as asbestos, a recognized carcinogen.

From Reuters • Dec. 14, 2018

He said the company now believes that the actinolite the Dartmouth professor found “was not asbestiform,” based on its interpretation of a photo in the original lab report.

From Reuters • Dec. 14, 2018

The actinolite slate is dark green, and formed by an almost insensible gradation from the mica slate.

From In the Arctic Seas A Narrative of the Discovery of the Fate of Sir John Franklin and his Companions by McClintock, Francis Leopold