Cummingtonite or magnesium iron silicate hydroxide is a metamorphic index mineral with the chemical composition (Mg,Fe)₇Si₈O₂₂(OH)₂. It is a member of the cummingtonite-grunerite solid solution series which ranges from Fe₂Mg₅Si₈O₂₂(OH)₂ for cummingtonite to the iron rich grunerite endmember Fe₇Si₈O₂₂(OH)₂. Manganese also substitutes for iron producing a manganese rich variety. The cummingtonite series is polymorphic with the anthophyllite-gedrite series and often requires optical or X-ray diffraction analysis to distinguish the polymorphs. Minerals are natural compounds formed through geological processes. ... A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... 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. ... In chemistry, a silicate is a compound consisting of silicon and oxygen (SixOy), one or more metals, and possibly hydrogen. ... Rose des Sables (Sand Rose), formed of gypsum crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... In crystallography, the monoclinic crystal system is one of the 7 lattice point groups. ... It has been suggested that twin boundary be merged into this article or section. ... Cleavage, in mineralogy, is the tendency of crystalline materials to split along definite planes, creating smooth surfaces, of which there are several named types: Basal cleavage: cleavage parallel to the base of a crystal, or to the plane of the lateral axes. ... A fracture is the separation of a body into two, or more, pieces under the action of stress. ... 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 (or index of refraction) of a material is the factor by which the phase velocity of electromagnetic radiation is slowed in that material, relative to its velocity in a vacuum. ... Relative density (also known as specific gravity) is a measure of the density of a material. ... Minerals are natural compounds formed through geological processes. ... The chemical composition of a substance refers to the elements of which the substance is composed. ... Grunerite is a mineral of the amphibole group of minerals with formula Fe7Si8O22(OH)2. ... A binary phase diagram displaying solid solutions over the full range of relative concentrations. ... Anthophyllite is an amphibole mineral: (Mg, Fe)7Si8O22(OH)2, magnesium iron inosilicate hydroxide. ... X-ray crystallography is a technique in crystallography in which the pattern produced by the diffraction of x-rays through the closely spaced lattice of atoms in a crystal is recorded and then analyzed to reveal the nature of that lattice. ... In general, a polymorph is something that can exist in several states or forms. ...

Amosite is a rare asbestiform variety of grunerite that is mined as asbestos only in the eastern part of the Transvaal Province of South Africa. The origin of the name is Amosa, the acronym for the mining company "Asbestos Mines of South Africa." Amosite is a commonly commercially-used synonym of grunerite first used by Hall. ... Fibrous asbestos on muscovite Asbestos Asbestos Asbestos (a misapplication of Latin: asbestos quicklime from Greek ἄσβεστος: a-, not; sbestos, extinguishable) describes any of a group of fibrous metamorphic minerals of the hydrous magnesium silicate variety. ...

Cummingtonite was first described in 1824 for an occurrence near Cummington, Massachusetts, hence the name. It is also found in Sweden, South Africa, and Scotland. Cummington is a town located in Hampshire County, Massachusetts. ... Motto: Nemo me impune lacessit (English: No one provokes me with impunity) Scotlands location within Europe Scotlands location within the United Kingdom Languages English, Gaelic, Scots Capital Edinburgh Largest city Glasgow First Minister Jack McConnell Area - Total - % water Ranked 2nd UK 78,782 km² 1. ...

Occurrence

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You get the picture?

References

• Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., Wiley, ISBN 0471805807
• Klein, Cornelius., 2002, The Manual of Mineral Science, 22nd ed., John Wiley & Sons, Inc. ISBN 0-471-25177-1
• Mineral Galleries
• Webmineral data
• Mindat

External links

• Molecules with Silly or Unusual Names