Silicate magnesium-iron

Actinolite— A mineral in the amphibole group, a calcium magnesium (iron) silicate with the chemical formula Ca2(Mg,Fe)5Sig022(0H)2. The mineral occurs as a series in which magnesium and iron can freely substitute for each other. Actinolite is the intermediate member when iron is predominant the mineral is ferro-actinolite and when magnesium is predominant, the mineral is tremolite. The iron produces a green color that darkens as the iron content increases. Actinolite may occur in fibrous form (an asbestos). It is not used commercially, but is a common impurity in chrysotile asbestos. 

Olivine A magnesium iron silicate mineral with the common solid solution endmembers forsterite and fayalite. 

Basalt Dark, fine-grained igneous rock composed mostly of plagioclase (a calcium-sodium silicate mineral) and pyroxene (a magnesium iron silicate mineral). 

The planet Earth was thus formed. Heat was created as the coalescence (of planetesimals) proceeded due to gravity, and heat also came from radioactivity of several radioactive elements such as aluminum-26. So the newly formed body was heated and the core was melted. As the material becomes liquid (as a result of melting), the materials contained in the liquid separate out according to their densities. The more dense material would sink closer to the bottom (core). Thus, the present layer structure of the Earth formed. The innermost core is a dense solid of about 1,200 km radius, whose density is about 12.6 g per cubic centimeter (12.6 x 10 kg/m ). It is made of mostly iron metal and a small amount of nickel. By the way, the density of iron metal is only 7.8 x 10 kg/m under the ordinary pressure. The next layer is the outer core (up to 3,500 km from the center of the Earth), which is liquid and has a density of 9.5-12x10 kg/m. The chemical composition seems to be about the same as that of the inner core. There is an abrupt change in density in the next layer, mantle. The width of mantle is about 2,900 km (3,500-6,380 km from the center). Its density ranges from 4 to 5.5 x 10 kg/m. The mantle is made of mostly magnesium-iron silicates (silicon oxides). The outermost layer is the thin crust of about 35 5 km on the land portion, and about 6 km under the ocean portion. 

Anthophyllite an(t)-tho- fi- llt, ( )an- tha-foA n [Gr for Anthophyllit, fr. NL anthophyllum, fr. Gk anthos + phyllon leaf] (ca. 1828) A type of Asbestos, the major source which is in Finland. Anthophyllite is a natural magnesium iron silicate, formerly used as a filler in polypropylene to provide heat stability. 

Let us briefly list some minerals that are frequently found in meteorites Olivine a magnesium iron silicate.The formula is ... 

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