Dravite, also called brown tourmaline, is the sodium magnesium rich tourmaline endmember. Uvite, in comparison, is a calcium magnesium tourmaline. Dravite forms multiple series, with other tourmaline members, including schorl and elbaite.[8]
The name dravite was used for the first time by Gustav Tschermak (1836–1927), Professor of Mineralogy and Petrography at the University of Vienna, in his book Lehrbuch der Mineralogie (published in 1884) for magnesium-rich (and sodium-rich) tourmaline from village Dobrova near Unterdrauburg in the Drava river area, Carinthia, Austro-Hungarian Empire. Today this tourmaline locality (type locality for dravite) at Dobrova (near Dravograd), is a part of the Republic of Slovenia.[9] Tschermak gave this tourmaline the name dravite, for the Drava river area, which is the district along the Drava River (in German: Drau, in Latin: Drave) in Austria and Slovenia. The chemical composition which was given by Tschermak in 1884 for this dravite approximately corresponds to the formula NaMg3(Al,Mg)6B3Si6O27(OH), which is in good agreement (except for the OH content) with the endmember formula of dravite as known today.[9]
Dravite varieties include the deep green chromium dravite and the vanadium dravite.[10]
References
Citations
GIA Gem Reference Guide. Gemological Institute of America. 1995. ISBN 0-87311-019-6.
"Tourmaline". Mindat.org. Archived from the original on 2005-12-28. Retrieved 2005-09-12. This website details specifically and clearly how the complicated chemical formula is structured.
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.
"tourmaline". Oxford Dictionaries. Archived from the original on October 16, 2021. Retrieved 2021-03-19.
Erhart, Jiri; Kittinger, Erwin; Prívratská, Jana (2010). Fundamentals of Piezoelectric Sensorics: Mechanical, Dielectric, and Thermodynamical Properties of Piezoelectric Materials. Springer. p. 4. ISBN 9783540684275.
Draper, John William (1861). A Textbook on chemistry. New York: Harper and Brothers. p. 93.
Ertl, 2006.
"What is Tourmaline? – GIA".
Ertl, 2007.
"Tourmaline Information – Gemstone Education".
GME Books
https://shorturl.at/yHHQJ
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