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|System:||Trigonal||Colour:||Dark brown to brownish ...|
|Name:||Named for Pavel Povondra (b. 1924-), mineralogist at Charles University, Prague, Czech Republic.|
Povondraite was redefined (IMA 90-E) from the original “ferridravite” (Walenta and Dunn 1979) because the initially assumed site assignments were incorrect and did not correspond to the Fe3+-equivalent of dravite (Grice et al. 1993). Hawthorne and Henry (1999) suggested that Mg is ordered at the Z site and should be part of the end-member formula.
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Classification of Povondraite
|IMA status:||Redefined Approved 1990|
|Strunz 8th edition ID:||8/E.19-75|
|Nickel-Strunz 10th (pending) edition ID:||9.CK.05|
9 : SILICATES (Germanates)
C : Cyclosilicates
K : [Si6O18]12- 6-membered single rings, with insular complex anions
|Dana 7th edition ID:||126.96.36.199|
|Dana 8th edition ID:||188.8.131.52|
61 : CYCLOSILICATES Six-Membered Rings
3 : Six-Membered Rings with borate groups
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Type Occurrence of Povondraite
|Type Locality:||Cristalmayu valley, Cristalmayu, Cristalmayu subdistrict, Alto Chapare District, Chapare Province, Cochabamba Department, Bolivia|
|Place of Conservation of Type Material:||Smithsonian|
|Year of Discovery:||1979|
Occurrences of Povondraite
|Geological Setting:||Saltdome caprock|
Physical Properties of Povondraite
|Colour:||Dark brown to brownish black|
Crystallography of Povondraite
|Cell Parameters:||a = 16.18Å, c = 7.44Å|
|Ratio:||a:c = 1 : 0.46|
|Unit Cell Volume:||V 1,686.79 Å³ (Calculated from Unit Cell)|
Optical Data of Povondraite
|RI values:||nω = 1.820 nε = 1.751|
|Maximum Birefringence:||δ = 0.069|
Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
|Surface Relief:||Very High|
Chemical Properties of Povondraite
|Simplified for copy/paste:||NaFe3+3(Mg2Fe3+4)(Si6O18)(BO3)3(OH)3O|
|Essential elements:||B, Fe, H, Mg, Na, O, Si|
|All elements listed in formula:||B, Fe, H, Mg, Na, O, Si|
Relationship of Povondraite to other Species
|Member of:||Tourmaline Group|
|Other Members of Group:|
|Related Minerals - Nickel-Strunz Grouping):|
|Related Minerals - Dana Grouping):|
Other Names for Povondraite
|Health Warning:||No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.|
References for Povondraite
Walenta, K. & Dunn, P. J. (1979): Ferridravite, a new mineral of the tourmaline group from Bolivia. American Mineralogist, 64, 945-948.
Grice, J.D., T.S. Ercit, and F.C. Hawthorne (1993): Povondraite, a redefinition of the tourmaline ferridravite. American Mineralogist 78, 433-436.
Grew, E.S., and Anovitz, L.M. (1996) BORON: Mineralogy, Petrology and Geochemistry, second edition, as revised (2002).
New Minerals (1997), New Minerals 1990-1994.
Zacek, V., Petrov, A., and Hyrsl, J. (1998): Chemistry and origin of povondraite-bearing rocks from Alto Chapare, Cochabamba, Bolivia. Journal of the Czech Geological Society 43, 59-67.
Žáček, V., Frýda, J., Petrov, A. and Hyršl, J. (2000): Tourmalines of the povondraite-(oxy)dravite series from the caps rocks of meta-evaporite in Alto Chapare, Cochamba, Bolivia. Journal of the Czech Geological Society, 45, 3-12.
Best Localities for Povondraite
|Best of Species:||Povondraite|
Internet Links for Povondraite
Localities for Povondraite
The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
(TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.