amphibole

American  

[am-fuh-bohl] / ˈæm fəˌboʊl /

noun

Mineralogy.

1. any of a complex group of hydrous silicate minerals, containing chiefly calcium, magnesium, sodium, iron, and aluminum, and including hornblende, tremolite, asbestos, etc., occurring as important constituents of many rocks.

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amphibole British  

/ ˈæmfɪˌbəʊl /

noun

1. any of a large group of minerals consisting of the silicates of calcium, iron, magnesium, sodium, and aluminium, usually in the form of long slender dark-coloured crystals. Members of the group, including hornblende, actinolite, and tremolite, are common constituents of igneous rocks

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amphibole Scientific  

/ ăm′fə-bōl′ /

1. Any of a large group of usually dark minerals composed of a silicate joined to various metals, such as magnesium, iron, calcium or sodium. Amphiboles occur as columnar or fibrous prismatic crystals in igneous and metamorphic rocks. Most are monoclinic, but some are orthorhombic. Hornblende, actinolite and glaucophane are amphiboles. Chemical formula: (Mg,Fe,Ca,Na) _2-3 (Mg,Fe,Al) ₅ (Si,Al) ₈ O ₂₂ OH ₂ .

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Etymology

Origin of amphibole

1600–10; < French < Late Latin amphibolus amphibolous

Example Sentences

The most common amphibole, hornblende, is usually black; however, they come in a variety of colors depending on their chemical composition.

From Textbooks • Jan. 1, 2017

The metamorphic rock, amphibolite, is primarily composed of amphibole minerals.

From Textbooks • Jan. 1, 2017

Similarly, a gneiss that originated as basalt and is dominated by amphibole, is an amphibole gneiss or, more accurately, an amphibolite.

From Textbooks • Jan. 1, 2015

At 15 km to 20 km, larger micas form to produce schist, and at 20 km to 25 km amphibole, feldspar, and quartz form to produce gneiss.

From Textbooks • Jan. 1, 2015

These lavas, destitute of amphibole and mica, are of a blackish brown, often varying to the deepest olive green.

From Personal Narrative of Travels to the Equinoctial Regions of America, During the Year 1799-1804 — Volume 1 by Ross, Thomasina