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|System:||Trigonal||Colour:||brown, brown-black, ...|
|Name:||For its relationship to dravite, although it is NOT an analogue of dravite (see below).|
Oxy-dravite has been used as a preliminary working name for a much-studied new member of the tourmaline group which has already appeared several times in the mineralogical literature. It was subnitted and approved as a new species by the IMA in 2012.
This species is related to dravite by substitution of one OH by (ideally) one O, the altered charge balance being compensated by replacing one Mg by a trivalent Al/Fe. This different charge balance means that "oxy-dravite" is not a true analogue of dravite.
Compare also oxy-schorl.
Originally (as an unapproved species) reported from Alto Chapare District, Chapare Province, Cochabamba Department, Bolivia.
Classification of Oxy-dravite
|IMA status:||Approved 2012|
|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
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Type Occurrence of Oxy-dravite
|Type Locality:||Osarara, Narok District, Rift Valley Province, Kenya|
|Place of Conservation of Type Material:||Museum of Mineralogy, Earth Sciences Department, Sapienza University of Rome, Rome, Italy, catalogue number 33066 |
Physical Properties of Oxy-dravite
|Colour:||brown, brown-black, red-black|
Crystallography of Oxy-dravite
|Class (H-M):||3m - Ditrigonal Pyramidal|
|Space Group Setting:||R3m|
|Cell Parameters:||a = 15.9273(2) Å, c = 7.2001(1) Å|
|Ratio:||a:c = 1 : 0.452|
|Unit Cell Volume:||V 1,581.81 Å³ (Calculated from Unit Cell)|
|X-Ray Powder Diffraction:|
Chemical Properties of Oxy-dravite
|Simplified for copy/paste:||Na(MgAl2)MgAl5(Si6O18)(BO3)3(OH)3O|
|Essential elements:||Al, B, H, Mg, Na, O, Si|
|All elements listed in formula:||Al, B, H, Mg, Na, O, Si|
Relationship of Oxy-dravite to other Species
|Member of:||Tourmaline Group|
|Other Members of Group:|
|Related Minerals - Nickel-Strunz Grouping):|
Other Names for Oxy-dravite
|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 Oxy-dravite
Hawthorne, F.C. & Henry, D.J. (1999): "Classification of the minerals of the tourmaline group", Eur. J. Mineral. 11:201-215.
Zacek, V., Fryda, J., Petrov, A., Hyrsl, J. (2000): "Tourmalines of the povondraite - (oxy)dravite series from the cap rock of meta-evaporite in Alto Chapare, Cochabamba, Bolivia", Journal of the Czech Geological Society 45:1-2, 3-12.
Novák, M., Povondra, P. & Selway, Julie B. (2004): Schorl-oxy-schorl to dravite-oxy-dravite tourmaline from granitic pegmatites; examples from the Moldanubicum, Czech Republic. European Journal of Mineralogy 16, 323-333.
Bosi, F. and Skogby, H. (2012): Oxy-dravite, IMA 2012-004a. CNMNC Newsletter No. 14, October 2012, page 1285; Mineralogical Magazine, 76, 1281-1288.
Renata Čopjaková, Radek Škoda & Michaela Vašinová Galiová (2012): „Oxy-dravit“ z turmalinitů krkonošsko-jizerského krystalinika [„Oxy-dravite“ from tourmalinites of the Krkonoše-Jizera Crystalline Massif]. Bull. mineral.-petrolog. Odd. Nár. Muz. (Praha) 20 ( 1), 37-46.
Bosi, F. and Skogby, H. (2013): Oxy-dravite, Na(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup. Am. Mineral. 98, 1442-1448.
Gatta, G., D, Bosi, F., McIntyre, G. J., and Skogby, H. (2014): First accurate location of two proton sites in tourmaline: A single-crystal neutron diffraction study of oxy-dravite. Mineralogical Magazine 78, 681-692.
Best Localities for Oxy-dravite
|Best of Species:||Oxy-dravite|
Internet Links for Oxy-dravite
Localities for Oxy-dravite
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.
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