#amphibole group
- Actinolite — A mineral belonging to the monoclinic amphibole group, with the chemical formula Ca2(Mg,Fe)5Si8O22(OH)2, characterized by a dark green or leek-green color. Structurally, it develops as acicular, fibrous, or radiating aggregates, being a common constituent of metamorphic rocks (such as greenschists). Its compact fibrous variety constitutes one of the mineral forms known as asbestos, while the dense microcrystalline variety forms nephrite (a type of jade).
- Anthophyllite — A natural magnesium and iron silicate, crystallizing in the orthorhombic system, belonging to the magnesium amphibole group; a mineral with a lamellar, fibrous, or prismatic structure, colored gray, brown, or greenish, found chiefly in metamorphic rocks (crystalline schists). Its fibrous varieties are industrially utilized as asbestos resistant to acids and high temperatures, though their handling involves severe respiratory toxicity risks.