390 likes | 1.24k Views
Tourmaline. EOSC 220 – November 23, 2004. Table 2. Additional hypothetical tourmaline end member species inferred from probable site occupancies (not currently recognized by IMA). Alkali tourmaline. Trigonal – Ditrigonal Pyramidal.
E N D
Tourmaline EOSC 220 – November 23, 2004
Table 2. Additional hypothetical tourmaline end member species inferred from probable site occupancies (not currently recognized by IMA) Alkali tourmaline Trigonal – Ditrigonal Pyramidal **These endmembers are theoretically possible, but not likely due to X-site vacancy - F avoidance that appears to take place in tourmaline.
Table 1. Current tourmaline end member species accepted by IMA Alkali tourmaline Calcic tourmaline X-site vacant tourmaline * These end-members are modified from the original suggested formulae to produce proper end-members (Hawthorne and Henry, 1999).
Buergerite • NaFe+3Al6(BO3)3Si6O21F • in cavities in a rhyolite • Bronze, Dark brown, Black • From near Mexquitic, San Luis Potosi, Mexico
Chromdravite • NaMg3(Cr,Fe+3)6(BO3)3Si6O18(OH)4 • Greenish black, Dark green • Onega trough, Karelia Republic, Northern Region, Russia
Dravite • NaMg3Al6(BO3)3Si6O18(OH)4 • Metasomatically altered magnesian or dolomitic limestones in contact-metamorphic aureoles • Black, Green, Red, Blue, White • Drava River, Austria
Feruvite • (Ca,Na)(Fe,Mg,Ti)3(Al,Mg,Fe)6(BO3)3Si6O18(OH)4 • Brownish black, Dark brown, Black • Repanga Island (Cuvier Island), Waikato, North Island, New Zealand
Foitite • Na<0.5(Fe+2,Al)3Al6Si6O18(BO3)3(OH)4 • Bluish black • California
Liddicoatite • Ca(Li,Al)3Al6(BO3)3Si6O18(O,OH,F)4 • Blue, Brown, Green, Pink, Red • Detrital in soil, product of pegmatites • From Antsirabe, Tsilaizina, and Anjanabonoina, Madagascar
Olenite • NaAl3Al6(BO3)3(Si6O18)(O,OH)4 • Light pink • Aluminum-rich tourmaline. Forms a series with elbaite • Decembrist pegmatite field, Olenik River Basin, Russia
Povondraite • (Na,K)(Fe+3,Fe+2)3(Fe,Mg,Al)6(BO3)3Si6O18(OH)4 • Black • Alto Chapare district, Chapare Province, Cochabamba, Bolivia
Schorl • NaFe+3Al6(BO3)3Si6O18(OH)4 • Black, Brownish black, Greenish black, Bluish black • Granites, diorites, gabbro pegmatites, greisens, skarns and quartz veins • Sonnenberg, Bodenmais and Spessart, Germany
Uvite • (Ca,Na)(Mg,Fe+2)3Al5Mg(BO3)3Si6O18(OH,F)4 • Yellowish brown, Brown, Blackish brown, Bluish black • Pegmatitic and skarn rocks • Province Uva, Sri Lanka
Vanadiumdravite • NaMg3V6(Si6O18)(BO3)3(OH)4 • Dark green, Black • Accessory mineral in metamorphic rocks with quartz and Cr-V bearing diopside • Slyudyanka complex, Lake Baikal region, Zabaikalye (Transbaikal), Siberia, Russia
Elbaite • Na(Li,Al)3Al6(BO3)3Si6O18(OH)4 • Blue, Colorless, Green, Yellow, White • Granitic pegmatites characterized by hydrothermal replacement • Island of Elba, Italy