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

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

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

“Occasionally, sub-trace quantities of tremolite or actinolite are identifiable,” he wrote in an April 1973 report on the visit.

From Reuters • Dec. 14, 2018

Some authors believe that the development of saussurite from felspar is also dependent on pressure rather than on weathering, and an analogous change may affect the olivine, replacing it by talc, chlorite, actinolite and garnet.

From Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4 "G" to "Gaskell, Elizabeth" by Various