- actinolite
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—actinolitic /ak tin'l it"ik, ak'teuh nl-/, adj./ak tin"l uyt', ak"teuh nl-/, n. Mineral.a variety of amphibole, occurring in greenish bladed crystals or in masses.[1825-35; ACTINO- + -LITE]
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Colourless to green amphibole mineral, darkening with increased iron content from green to black.It has a prismatic and splintery texture and is abundant in regionally metamorphosed (see metamorphism) rocks such as schists. Actinolite has a monoclinic crystal structure, and it may alter to chlorite. See also asbestos.* * *
▪ mineralan amphibole mineral in the tremolite-actinolite series of calcium, magnesium, and iron silicates. The minerals in this series are abundant in regionally metamorphosed rocks, such as schists. Tremolite may weather to talc, and both tremolite and actinolite may alter to chlorite or carbonates. For chemical formula and detailed physical properties, see amphibole (table).The fibres of the magnesium-rich members in the series are asbestos; these varieties, sometimes known as amphibole asbestos, constitute the material to which the name asbestos was originally given. The fibres are fine and silky and possess appreciable tensile strength; those that occur in thin, felted sheets of interwoven fibres are called mountain leather; in thicker sheets, mountain cork; and in compact masses resembling dry wood, mountain wood.* * *
Universalium. 2010.