acmite

mineral

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July 23, 2026

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Acmite, also known as aegirine, is a mineral composed of sodium and iron silicate with the chemical formula NaFeSi₂O₆. It belongs to the pyroxene group of silicate minerals, which are characterized by one-dimensional chains of linked SiO₄ tetrahedrons. Acmite typically forms long, prismatic crystals that are brown or green in color and have a hardness of 6 to 6.5. It is commonly found in alkaline igneous rocks, such as syenites. Acmite forms a continuous chemical series with aegirine-augite, where calcium can substitute for sodium, and magnesium and aluminum can replace iron.1234

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aegirine
In this series, the name acmite is given to crystals with the composition NaFeSi₂O₆ as well as to the reddish brown or greenish black pointed crystals approximating that composition. Aegirine generally is restricted to the dark green to greenish black, blunt crystals of the same composition. For detailed physical properties,…
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In this series, the name acmite is given to crystals with the composition NaFeSi₂O₆ as well as to the reddish brown or greenish black pointed crystals approximating that composition. Aegirine generally is restricted to the dark green to greenish black, blunt crystals of the same composition. For detailed physical properties,…
Read More