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Actinolite is an amphibole
Amphibole

Amphibole defines an important group of generally dark-colored rock-forming Silicate minerals minerals, composed of double chain SiO4 tetrahedron, linked at the vertices and generally containing ions of iron and/or magnesium in their structures....
 silicate mineral
Silicate minerals

The silicate minerals make up the largest and most important class of rock-forming minerals, comprising approximately 90 percent of the crust of the Earth....
 with the chemical formula .

nolite is an intermediate member in a solid-solution
Solid solution

A solid solution is a solid-phase solution of one or more soluble in a solvent. Such a mixture is considered a solution rather than a Chemical compound when the crystal structure of the solvent remains unchanged by addition of the solutes, and when the mixture remains in a single wiktionary:Homogeneous phase ....
 series between magnesium-rich tremolite
Tremolite

Tremolite is a member of the amphibole group of silicate minerals with composition: calcium2magnesium5silicon8oxygen222....
, , and iron-rich ferro-actinolite, . Mg and Fe ion
Ion

An ion is an atom or molecule which has lost or gained one or more electrons, giving it a positive or negative electrical charge. According to the Bohr_model this will be from or in the outer shield 'n'....
s can be freely exchanged in the crystal
Crystal

A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions....
 structure. Like tremolite, asbestiform
Asbestiform

Asbestiform implies a particular kind of fibrosity in which fibers have high tensile strength and flexibility....
 actinolite is regulated as asbestos
Asbestos

Asbestos is a naturally occurring silicate mineral with long, thin fibrous crystals. The word asbestos is derived from a Greek language adjective meaning inextinguishable....
.

nolite is commonly found in metamorphic rock
Metamorphic rock

Metamorphic rock is the result of the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form"....
s, such as contact aureoles surrounding cooled intrusive igneous rock
Igneous rock

Igneous rock is one of the three main Rock types . Igneous rock is formed by magma being cooled and becoming solid . They may form with or without crystallization, either below the surface as Intrusion rocks or on the surface as extrusive rocks....
s. It also occurs as a product of metamorphism
Metamorphism

Metamorphism is the solid-state Crystallization of pre-existing Rock due to changes in physical and chemical conditions, primarily heat, pressure, and the introduction of chemically active fluids....
 of magnesium-rich limestone
Limestone

File:Limestone Formation In Waitomo.jpgLimestone is a sedimentary rock composed largely of the mineral calcite . The deposition of limestone strata is often a by-product and indicator of biological activity in the geology record....
s.

The old mineral name uralite is at times applied to an alteration product of primary pyroxene
Pyroxene

The pyroxenes are a group of important rock-forming silicate minerals found in many igneous and metamorphic rock rock . They share a common structure comprised of single chains of silica tetrahedra and they crystallize in the monoclinic and orthorhombic systems....
 by a mixture composed largely of actinolite.






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Encyclopedia


Actinolite is an amphibole
Amphibole

Amphibole defines an important group of generally dark-colored rock-forming Silicate minerals minerals, composed of double chain SiO4 tetrahedron, linked at the vertices and generally containing ions of iron and/or magnesium in their structures....
 silicate mineral
Silicate minerals

The silicate minerals make up the largest and most important class of rock-forming minerals, comprising approximately 90 percent of the crust of the Earth....
 with the chemical formula .

Mineralogy

Actinolite is an intermediate member in a solid-solution
Solid solution

A solid solution is a solid-phase solution of one or more soluble in a solvent. Such a mixture is considered a solution rather than a Chemical compound when the crystal structure of the solvent remains unchanged by addition of the solutes, and when the mixture remains in a single wiktionary:Homogeneous phase ....
 series between magnesium-rich tremolite
Tremolite

Tremolite is a member of the amphibole group of silicate minerals with composition: calcium2magnesium5silicon8oxygen222....
, , and iron-rich ferro-actinolite, . Mg and Fe ion
Ion

An ion is an atom or molecule which has lost or gained one or more electrons, giving it a positive or negative electrical charge. According to the Bohr_model this will be from or in the outer shield 'n'....
s can be freely exchanged in the crystal
Crystal

A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions....
 structure. Like tremolite, asbestiform
Asbestiform

Asbestiform implies a particular kind of fibrosity in which fibers have high tensile strength and flexibility....
 actinolite is regulated as asbestos
Asbestos

Asbestos is a naturally occurring silicate mineral with long, thin fibrous crystals. The word asbestos is derived from a Greek language adjective meaning inextinguishable....
.

Occurrence

Actinolite is commonly found in metamorphic rock
Metamorphic rock

Metamorphic rock is the result of the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form"....
s, such as contact aureoles surrounding cooled intrusive igneous rock
Igneous rock

Igneous rock is one of the three main Rock types . Igneous rock is formed by magma being cooled and becoming solid . They may form with or without crystallization, either below the surface as Intrusion rocks or on the surface as extrusive rocks....
s. It also occurs as a product of metamorphism
Metamorphism

Metamorphism is the solid-state Crystallization of pre-existing Rock due to changes in physical and chemical conditions, primarily heat, pressure, and the introduction of chemically active fluids....
 of magnesium-rich limestone
Limestone

File:Limestone Formation In Waitomo.jpgLimestone is a sedimentary rock composed largely of the mineral calcite . The deposition of limestone strata is often a by-product and indicator of biological activity in the geology record....
s.

The old mineral name uralite is at times applied to an alteration product of primary pyroxene
Pyroxene

The pyroxenes are a group of important rock-forming silicate minerals found in many igneous and metamorphic rock rock . They share a common structure comprised of single chains of silica tetrahedra and they crystallize in the monoclinic and orthorhombic systems....
 by a mixture composed largely of actinolite. The metamorphosed gabbro
Gabbro

Gabbro refers to a large group of dark, coarse-grained, intrusive igneous rock chemically equivalent to basalt. The rocks are Intrusive, formed when molten magma is trapped beneath the Earth's surface and cools into a crystalline mass....
 or diabase
Diabase

Diabase or Dolerite is a mafic, holocrystalline, intrusion igneous rock equivalent to volcanic basalt or intrusion gabbro. In North American usage the term diabase refers to the fresh rock, whilst elsewhere the term dolerite is used for the fresh rock and diabase refers to altered material.....
 rock
Rock (geology)

In geology, rock is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock....
 bodies, referred to as epidiorite, contain a considerable amount of this uralitic alteration.

Some forms of asbestos are formed from fibrous actinolite, the fibres being so small that they can enter the lung
Lung

The lung is the essential respiration organ in air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located in the chest on either side of the heart....
s and damage the alveoli.

Gemology

Some forms of actinolite are used as gemstone
Gemstone

A gemstone or gem, also called a precious or semi-precious stone, is a piece of attractive mineral, which — when cut and polished — is used to make jewellery or other adornments....
s. One is nephrite
Nephrite

Nephrite is a variety of the calcium and magnesium-rich amphibole mineral actinolite . The chemical formula for nephrite is calcium25silicon8oxygen222....
, one of the two types of jade
Jade

Jade is an ornamental stone.The term jade is applied to two different metamorphic rocks that are made up of different silicate minerals:...
 (the other being jadeite
Jadeite

Jadeite is a pyroxene mineral with composition sodiumaluminumsilicon2oxygen6. It is monoclinic. It has a Mohs hardness of about 6.5 to 7.0 depending on the composition....
, a variety of pyroxene).

Another gem variety is the chatoyant form known as cat's-eye actinolite. This stone is translucent to opaque, and green to yellowish green color. This variety has had the misnomer jade cat's-eye. Transparent actinolite is rare and is faceted for gem collectors. Major sources for these forms of actinolite are Taiwan
Taiwan

Taiwan is an island in East Asia. "Taiwan" is also commonly used to refer to the country governed by the Republic of China and to the ROC itself, which governs the island of Taiwan, Orchid Island and Green Island, Taiwan in the Pacific Ocean off the Taiwan coast, the Penghu islands in the Taiwan Strait, and Kinmen and the Matsu Islands...
 and Canada
Canada

Canada is a country occupying most of northern North America, extending from the Atlantic Ocean in the east to the Pacific Ocean in the west and northward into the Arctic Ocean....
. Other sources are Madagascar
Madagascar

Madagascar, or Republic of Madagascar , is an island nation in the Indian Ocean off the southeastern coast of Africa. The main island, also called Madagascar, is the List of islands by area, and is home to 5% of the world's plant and animal species, of which more than 80% are Endemism to Madagascar....
, Tanzania
Tanzania

Tanzania , officially the United Republic of Tanzania , is a country in East Africa that is bordered by Kenya and Uganda on the north, Rwanda, Burundi and the Democratic Republic of the Congo on the west, and Zambia, Malawi and Mozambique on the south....
, and the US.