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arfvedsonite
mineral
- Related Topics:
- eckermannite
- sodic amphibole group
arfvedsonite, amphibole mineral, an iron-rich sodium silicate. Lithium and magnesium replace iron in the structure to form eckermannite. Both minerals characteristically occur as dark-green crystals in alkali igneous rocks and their associated pegmatites. For chemical formula and detailed physical properties, see amphibole (table).