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Chromio-pargasite
A valid IMA mineral species
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About Chromio-pargasite
Formula:
NaCa2(Mg4Cr)(Si6Al2)O22(OH)2
Chromio-Pargasite is defined as a pargasite-group member with the following dominant elements:
A position: Na
C position: Mg as the dominant divalent cation and Cr as the dominant trivalent cation.
W position: (OH) as the dominant anion
A position: Na
C position: Mg as the dominant divalent cation and Cr as the dominant trivalent cation.
W position: (OH) as the dominant anion
Colour:
Emerald green to pale green
Lustre:
Vitreous
Hardness:
6
Specific Gravity:
3.08
Crystal System:
Monoclinic
Member of:
Name:
In the original description it was named ehimeite after the locality where it was found in the Ehime Prefecture, Japan. It was renamed very shortly afterward to chromio-pargasite, following the 2012 amphibole nomenclature, in order to create a consistant naming convention for the pargasite group minerals.
This mineral was originally named Ehimeite in the original description and the 2011 IMA approval of the species. It has been renamed Chromio-pargasite in the 2012 amphibole nomenclature in order to create a consistant naming convention for the pargasite group minerals.
Unique Identifiers
Mindat ID:
41970
Long-form identifier:
mindat:1:1:41970:9
IMA Classification of Chromio-pargasite
Approved
IMA Formula:
NaCa2(Mg4Cr3+)(Si6Al2)O22(OH)2
Approval year:
2011
First published:
2012
Type description reference:
Nishio-Hamane, Daisuke, Ohnishi, Masayuki, Minakawa, Tetsuo, Yamaura, Jun-ichi, Saito, Shohei, Kadota, Ryo (2012) Ehimeite, NaCa2Mg4CrSi6Al2O22(OH)2: The first Cr-dominant amphibole from the Akaishi Mine, Higashi-Akaishi Mountain, Ehime Prefecture, Japan. Journal of Mineralogical and Petrological Sciences, 107 (1) 1-7 doi:10.2465/jmps.110715
Higashi-Akaishi dunite, Higashi-Akaishi Ultrahigh-Pressure Peridotite Complex, Ehime Prefecture, Japan