Definitions for "Amphibole"
A common mineral embracing many varieties varying in color and in composition. It occurs in monoclinic crystals; also massive, generally with fibrous or columnar structure. The color varies from white to gray, green, brown, and black. It is a silicate of magnesium and calcium, with usually aluminium and iron. Some common varieties are tremolite, actinolite, asbestus, edenite, hornblende (the last name being also used as a general term for the whole species). Amphibole is a constituent of many crystalline rocks, as syenite, diorite, most varieties of trachyte, etc. See Hornblende.
An important rock-forming mineral group of mafic silicates. Amphibole crystals are constructed from double chains of silicon-oxygen tetrahedra. Example: hornblende.
A group of silicate minerals having a characteristic crystal form and cleavage. Can be considered as metasilicates, but of complex composition.