Anorthite is one of the plagioclase feldspars, an important group of minerals abundant in the Earth's crust. Anorthite's chemical formula is CaAl₂Si₂O₈. Feldspar (from the German Feld, field, and Spat, a rock that does not contain ore) is the name of an important group of rock-forming minerals which make up perhaps as much as 60% of the Earths crust. ... Minerals are natural compounds formed through geological processes. ...

Mineralogy

Anorthite is the calcium-rich endmember of the plagioclase system, the other endmember being albite (sodium-rich). The range of intermediate compositions have varying ratios of calcium and sodium ions. General Name, Symbol, Number calcium, Ca, 20 Series alkaline earth metal Group, Period, Block 2 (IIA), 4, s Density, Hardness 1550 kg/m3, 1. ... Feldspar (from the German Feld, field, and Spat, a rock that does not contain ore) is the name of an important group of rock-forming minerals which make up perhaps as much as 60% of the Earths crust. ... General Name, Symbol, Number sodium, Na, 11 Series alkali metal Group, Period, Block 1 (IA), 3, s Density, Hardness 968 kg/m3, 0. ... An ion is an elementary particle or system of elementary particles with a net electric charge. ...

Occurrence

Anorthite occurs in igneous and metamorphic rocks. Its type localities are Monte Somma and Valle di Fassa, Italy, Volcanic rock on North America Plutonic rock on North America Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... Metamorphism can be defined as the mineralogical, chemical and crystallographic changes in a solid-state rock, i. ...

Details

Rose des Sables (Sand Rose), a formation of gypse crystal In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer. ... The refractive index of a material is the factor by which electromagnetic radiation is slowed down (relative to vacuum) when it travels inside the material. ... Pleochroism is an optical phenomenon where due to double refraction of light by a colored gem or crystal, the light is divided into two paths which are polarized at a 90° angle to each other. ...

See also

• Feldspars
• List of minerals

Feldspar (from the German Feld, field, and Spat, a rock that does not contain ore) is the name of an important group of rock-forming minerals which make up perhaps as much as 60% of the Earths crust. ... Gem animals. ...

External link

• WebMineral entry