The Collaborative International Dictionary
Amphibole \Am"phi*bole\ ([a^]m"f[i^]*b[=o]l), n. [Gr. 'amfi`bolos doubtful, equivocal, fr. 'amfiba`llein to throw round, to doubt: cf. F. amphibole. Ha["u]y so named the genus from the great variety of color and composition assumed by the mineral.] (Min.) 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.
n. (context geology English) A large group of structurally similar hydrated double silicate minerals, containing various combinations of sodium, calcium, magnesium, iron, and aluminium/aluminum
n. a mineral or mineral variety belonging to the amphibole group
Amphibole is the name of an important group of generally dark-colored, inosilicate minerals, forming prism or needlelike crystals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Amphiboles can be green, black, colorless, white, yellow, blue, or brown. The International Mineralogical Association currently classifies amphiboles as a mineral supergroup, within which are two groups and several subgroups.
Usage examples of "amphibole".
That one’s silicate–mostly amphibole, the gear on the rocket told us years ago right after the landing, but this will be the first time we’ll be able to tell anything about the other layers.