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- Rock-forming
ferromagnesian silicate
mineral that
crystallizes
early from magma and weathers readily at earth's
surface. Crystal structure based on isolated (SiO4)4- ions and positive ions of iron, magnesium, or
both. General formula: (Mg, Fe)2SiO4.
Source: Leet, L. Don. 1982.
Physical Geology, 6th Edition. Englewood Cliffs, NJ: Prentice-Hall
- A mineral group including fayalite, Fe2 SiO4 ; forsterite,
Mg2 SiO4 ; liebenbergite, (Ni,Mg)2 SiO4 ; and
tephroite, Mn2 SiO4 ; orthorhombic; olive green, grayish
green, brown, or black; members intermediate in the forsterite-fayalite
crystal solution series are common rock-forming minerals in gabbros,
basalts, peridotites, and dunites; alters hydrothermally to serpentine.
Fayalite occurs in some granites and syenites, forsterite in thermally
metamorphosed dolomites, and tephroite in iron manganese ore deposits and
their associated skarns. Syn: peridot;
chrysolite; olivinoid.
Source:
Dictionary of Mining, Mineral, and Related Terms
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