tremolite

mineral

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July 14, 2026

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Tremolite is a white or gray mineral belonging to the amphibole group, which are common rock-forming silicate minerals. It is a silicate of calcium and magnesium. Amphiboles, including tremolite, are typically found in metamorphic and igneous rocks.12

Tremolite is part of the tremolite-actinolite series, which are abundant in regionally metamorphosed rocks like schists. The chemical formula for tremolite is Ca₂Mg₅Si₈O₂₂(OH)₂. Amphiboles are characterized by their double chain silicate structure and two directions of cleavage intersecting at approximately 56° and 124°.31

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amphibole
tremolite
actinolite
soda-tremolite

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amphibole
Chemical composition
Complete substitution extends from tremolite [Ca₂Mg₅Si₈O₂₂(OH)₂] to ferro-actinolite [Ca₂Fe₅Si₈O₂₂(OH)₂]. Actinolite is the intermediate member of the tremolite-ferro-actinolite series. The compositional range from about 0.9 Mg₇Si₈O₂₂(OH)₂ to about Fe₂
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Complete substitution extends from tremolite [Ca₂Mg₅Si₈O₂₂(OH)₂] to ferro-actinolite [Ca₂Fe₅Si₈O₂₂(OH)₂]. Actinolite is the intermediate member of the tremolite-ferro-actinolite series. The compositional range from about 0.9 Mg₇Si₈O₂₂(OH)₂ to about Fe₂
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amphibole
Regional metamorphic rocks
In magnesium-rich rocks, tremolite, anthophyllite, and hornblende may exist together. Gedrite and cummingtonite coexist with garnet in rocks enriched in aluminum and iron. Rocks containing cummingtonite or grunerite are characteristic of metamorphosed iron formations associated with iron oxides, iron-rich sheet silicates, carbonates, and quartz. Glaucophane occurs only in…
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In magnesium-rich rocks, tremolite, anthophyllite, and hornblende may exist together. Gedrite and cummingtonite coexist with garnet in rocks enriched in aluminum and iron. Rocks containing cummingtonite or grunerite are characteristic of metamorphosed iron formations associated with iron oxides, iron-rich sheet silicates, carbonates, and quartz. Glaucophane occurs only in…
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