ETYM Greek amphibolos doubtful, equivocal, from amphiballein to throw round, to doubt: cf. French amphibole. Haüy so named the genus from the great variety of color and composition assumed by the mineral.
A mineral or mineral variety belonging to the amphibole group.
Rock-forming silicate similar to asbestos and hornblende.
Any one of a large group of rock-forming silicate minerals with an internal structure based on double chains of silicon and oxygen, and with a general formula X2Y5Si8O22(O H)2; closely related to pyroxene. Amphiboles form orthorhombic, monoclinic, and triclinic crystals.
Amphiboles occur in a wide range of igneous and metamorphic rocks. Common examples are hornblende (X = Ca, Y = Mg, Fe, Al) and tremolite (X = Ca, Y = Mg).