Glaucophane

Glaucophane is a mineral belonging to the amphibole group, chemical formula Na₂(Mg,Fe)₃Al₂Si₈O₂₂(OH)₂. It is named from its typical blue color (in Greek, glaucophane means "blue appearing"). Glaucophane crystallizes in the monoclinic system. Image File history File linksMetadata Download high-resolution version (1474x1110, 1318 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Glaucophane Metadata This file contains additional information, probably added from the digital camera or scanner used to create... Image File history File linksMetadata Download high-resolution version (1474x1110, 1318 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Glaucophane Metadata This file contains additional information, probably added from the digital camera or scanner used to create... Minerals are natural compounds formed through geological processes. ... For the logical fallacy, see Amphibology. ...

The blue color is very diagnostic for this species. It, along with the closely related mineral riebeckite are the only common amphibole minerals that are typically blue. Glaucophane forms a solid solution series with ferroglaucophane; Na₂(Fe,Mg)₃Al₂Si₈O₂₂(OH)₂. Glaucophane is the magnesium-rich member and ferroglaucophane is the iron-rich member. Ferroglaucophane is similar to glaucophane but is denser, generally darker in color with a diminished pearly luster. Glaucophane's hardness is 5 - 6, and its specific gravity is approximately 3 - 3.2. Riebeckite is a sodium-rich member of the amphibole group of minerals, chemical formula Na2(Fe,Mg)5Si8O22(OH)2. ... General Name, Symbol, Number magnesium, Mg, 12 Chemical series alkaline earth metals Group, Period, Block 2, 3, s Appearance silvery white Atomic mass 24. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ... For the file system called Lustre, see Lustre (file system) Lustre (American English: luster) is a description of the way light interacts with the surface of a crystal, rock or mineral. ... In materials science, hardness is the characteristic of a solid material expressing its resistance to permanent deformation. ... Relative density (also known as specific gravity) is a measure of the density of a material. ...

Glaucophane forms in metamorphic rocks that are either particularly rich in sodium or that have experienced low temperature-high pressure metamorphism such as would occur along a subduction zone. This material has undergone intense pressure and moderate heat as it was subducted downward toward the mantle. It is glaucophane's color that gives the blueschist facies its name. Glaucophane is also found in eclogites that have undergone retrograde metamorphism. Quartzite, a form of metamorphic rock, from the Museum of Geology at University of Tartu collection. ... General Name, Symbol, Number sodium, Na, 11 Chemical series alkali metals Group, Period, Block 1, 3, s Appearance silvery white Atomic mass 22. ... Metamorphism can be defined as the mineralogical, chemical and crystallographic changes in a solid-state rock, i. ... The Juan de Fuca plate sinks below the North America plate at the Cascadia subduction zone. ... Earth cutaway from core to exosphere. ... Blueschist is a rock that forms by the metamorphism of sodium-rich basic rocks at high pressures and low temperatures, approximately corresponding to a depth of 15 to 30 kilometers and 200 to 400 degrees Celsius (cool by metamorphic standards). ... Eclogite is a coarse-grained, mafic-to-ultramafic grouping of metamorphic rocks of special interest on account of the variety of minerals they contain and their microscopic structures and geological relationships. ...

There is also a rare amphibole called Holmquistite, chemical formula Li₂Mg₃Al₂Si₈O₂₂(OH)₂, which occurs only in lithium-rich continental rocks. For many years, Holmquistite was mistaken for Glaucophane, as the two look identical in thin section.

See also

• List of Minerals