Foitite
Foitite | ||
---|---|---|
Mohs scale hardness | 7 |
Foitite is a mineral in the tourmaline group,[2] it is a vacancy-dominant member of the group.[3] Foitite is in the 'vacancy' group, due to the absence of atoms in the X site.[2]
According to the Czech Geological Society, foitite is rare.[4] However foitite is quite common among low-temperature tourmalines[5] and it might be more common than previously thought.[6]
The color of the mineral is dark indigo with purple tints to bluish-black.[3]
Name
The mineral was named in 1993 by D. J. MacDonald, Frank C. Hawthorne, and Joel D.Grice after Franklin F. Foit, Jr.[5]
Chemistry
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It lacks alkalis like sodium.[7]
Foitite is a member of the tourmaline mineral group, which is a complex aluminum borosilicate. The chemical formula of foitite is (NaFe3+Al6)(Al6Si6O18)(BO3)3(OH)4.
In this formula,
The crystal structure of foitite consists of continuous chains of
Foitite typically forms in
Occurrence
It occurs in quartz veins[9] and possibly occurs in granite pegmatites.[10]
Foitite has also been reported in Marquette County, Michigan.[6] Its type locality is California.[5]
It has been reported in Wales and it is predicted that a more widespread distribution of the mineral in Wales will be shown.[2]
References
- S2CID 235729616.
- ^ a b c "Mineral Database - Mineralogy of Wales". National Museum Wales. Retrieved 2021-10-12.
- ^ a b "Foitite gemstone information". www.gemdat.org. Retrieved 2021-10-28.
- ^ Journal of Geosciences. Czech Geological Society. 2010. p. 17.
- ^ a b c "Foitite". www.mindat.org. Retrieved 2021-10-12.
- ^ a b "Foitite" (PDF). The A. E. Seaman Mineral Museum. Retrieved 29 October 2021.
- ^ "Wisconsin Geological & Natural History Survey » Foitite". wgnhs.wisc.edu. Retrieved 2021-10-14.
- ^ UNIVERSITY of WISCONSIN–MADISON. "Foitite".
- CiteSeerX 10.1.1.615.277.
- ^ "Foitite" (PDF). Mineral Data Publishing. 2001. Retrieved 29 October 2021.