What is the use of anthophyllite?
The anthophyllite was used in asbestos cement and for insulation, roofing material etc. Anthophyllite is also known as azbolen asbestos.
What is andalusite used for?
Uses. Andalusite is used as a refractory in furnaces, kilns and other industrial processes. South Africa possesses by far the largest portion of the world’s known andalusite deposits.
How do you identify sillimanite?
Sillimanite. Sillimanite is a metamorphic mineral found in high grade aluminous schists and gneisses. It is a polymorph of andalusite and kyanite, all having formula Al2SiO5. Keys to identification are high relief, needle-like, fibrous or bladed habit, characteristic square cross sections with one diagonal cleavage.
How do you identify andalusite?
Keys to identification are high relief, low birefringence and parallel extinction. Color – generally colorless, rarely reddish. Often cloudy due to inclusions. Twinning – Although rarely seen in thin section, some andalusite shows distinctive penetration twins, forming a cross, that helps identify andalusite.
What is anthophyllite asbestos?
Anthophyllite Asbestos Like other types of asbestos in the amphibole family, anthophyllite is composed of long, needle-like fibers that can be easily inhaled into the lungs. Anthophyllite can range from brown to yellowish in color and is composed mainly of magnesium and iron.
Where can anthophyllite be found?
anthophyllite, an amphibole mineral, a magnesium and iron silicate that occurs in altered rocks, such as the crystalline schists of Kongsberg, Nor., southern Greenland, and Pennsylvania. Anthophyllite is commonly produced by regional metamorphism of ultrabasic rocks.
Is andalusite valuable?
Andalusite is on average $40 dollars per carat. However, andalusite gemstones that feature custom cuts, and a higher than average play of light and colors, are valued at higher prices. *Unlike most gemstones that are cut to minimize color play, andalusite is cut to maximize the full pleochroic effect.
What is sillimanite worth?
Sillimanite: average retail prices, May 2022
| Color Description, Occurrence | 1 ct. | 3 ct. |
|---|---|---|
| 062 – light yellowish Green; strong Alternative name, occurrence category: Common | $25.44/ct | $27.08/ct |
| 127 – very light very strongly greenish Blue Alternative name, occurrence category: Common | $33.11/ct | $35.25/ct |
Where can sillimanite be found?
Sillimanite is found at many points in France, Madagascar, and the eastern United States; a pale sapphire-blue gem variety occurs in the gravels of Sri Lanka. For detailed physical properties, see silicate mineral (table).
Does andalusite change color?
Andalusite displays different colors in different directions and features all its colors at once, whereas color change gems like alexandrite only change color when exposed to different light sources.
Where can andalusite be found?
andalusite, (Al2SiO5), aluminum silicate mineral that occurs in relatively small amounts in various metamorphic rocks, particularly in altered sediments. It is found in commercial quantities in the Inyo Mountains, Mono county, Calif., in the United States; in Kazakhstan; and in South Africa.