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.
A common dark rock-forming silicate mineral present in many igneous and metamorphic rocks. Examples are hornblende and anthophyllite (asbestos).
a mineral group composed mostly of some mixture of magnesium, iron, and calcium, with aluminum, silicon, and oxygen. It includes common rock-forming minerals characterized by flat, reflective breakage surfaces in two directions, which meet at about 60o angles. The most common amphibole minerals are hornblende, tremolite, actinolite, cummingtonite, and hypersthene.
A group of ferromagnesian minerals, usually dark in color, and common as constituents of many rocks. Hornblende is a mineral of this group, sometimes used as a catch-all term for amphibole.
The name for a group of silicate minerals, with a double chain structure, often found in metamorphic rocks.
One of the two subgroups of minerals forming the asbestos group, distinguished by their chain-like crystal structure and chemical composition. Asbestos amphiboles include actinolite, amosite, anthophyllite, crocidolite, and tremolite.
a mineral or mineral variety belonging to the amphibole group
a mineral that is composed of straight, needle-like fibers as opposed to the curled fibers of serpentine rocks
An amphibole is a group of silicate minerals containing crystal structures made up of some combination of calcium, sodium, magnesium, aluminum, and iron.
A complex family of silicate minerals with similar physical features and a general formula A0-1 X (Si,Al) 22(OH,F,CL) where A= Ca, Na, K; X = Ca, Fe, Mg, Mn, Na; Y = Al, Fe, Mg, Mn, Ti. Amphiboles form in both igneous and metamorphic environments. See hornblende.
A family of silicate minerals forming prism or needlelike crystals. Amphibole minerals generally contain iron, magnesium, calcium and aluminum in varying amounts, along with water. Hornblende always has aluminum and is a most common dark green to black variety of amphibole; it, forms forming in many igneous and metamorphic rocks. Actinolite has no aluminum; it and is needle-shaped and light green. Blue amphibole contains sodium and, of course, is bluish in color. more details...
A large group of silicate minerals with more than 40-50 members. The molecular structure of all amphiboles consists of two chains of SiO4 molecules that are linked together at the oxygen atoms. In the earth's crust, amphibole minerals are mostly nonasbestiform; asbestiform amphiboles are relatively rare. See definitions of asbestiform, mineral, and mineral habit.
a mineral group composed of varying amounts of magnesium, iron, aluminum (Al), calcium and sodium in a (SiAl4)O11(OH)2 base.
An important group of silicate minerals containing iron, magnesium and calcium.
A subgroup of asbestos characterized by crystals forming in a chain-like structure.
A mineral group with the general formula A2B5(Si,Al)8O22(OH)2, where A is mainly the metals Mg, Fe, Ca, or Na, and B is mainly Mg, Fe+2, Al, and Fe+3. This group includes some common minerals in igneous and metamorphic rocks.
a type of mineral, distinguished by a chain-like crystal structure and chemical composition. Asbestos amphiboles include actinolite, amosite, anthophillite, crocidolite, and tremolite.
A common mineral composed of silicate of magnesium and calcium, (with usually aluminum and iron), which occurs in monoclinic crystals and comes in many varieties, each varying in color and in composition. The color varies from white to gray, green, brown, and black. Jade is a form of Amphibole.