Margarite

Margarite is a calcium rich member of the mica group of the phyllosilicates with formula: CaAl2(Al2Si2)O10(OH)2. It forms white to pinkish or yellowish gray masses or thin laminae.[5] It crystallizes in the monoclinic crystal system. It typically has a specific gravity of around 3 and a Mohs hardness of 4. It is translucent with perfect 010 cleavage and exhibits crystal twinning.

Not to be confused with margarita.
Margarite
Margarite from the Wright Mine, Chester Emery Mines, Chester, Hampden County, Massachusetts, USA. Size: 4.8 x 3.4 x 2.6 cm.
General
CategoryMicas (phyllosilicates)
Formula
(repeating unit)		CaAl2(Al2Si2)O10(OH)2
IMA symbolMrg[1]
Strunz classification9.EC.30
Crystal systemMonoclinic
Crystal classDomatic (m)
(same H-M symbol)
Space groupCc
Identification
Colorflesh pink
Crystal habitplaty
Cleavagebasal
Mohs scale hardness4
References[2][3][4]

It occurs commonly as an alteration product of corundum, andalusite and other aluminous minerals. It has been reported as forming alteration pseudomorphs of chiastolite along with muscovite and paragonite. The margarite in this occurrence forms preferentially along the dark graphite rich inclusions with the chiastolite crystals.

Margarite is found in the emery deposits of Turkey and the Aegean islands, and with corundum at several localities in the United States.[5]

References
Wikimedia Commons has media related to Margarite.
  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. Mineralienatlas
  3. Mindat with location data
  4. Webmineral data
  5. Spencer 1911.


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