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Tourmaline EOSC 220 – November 23, 2004. Trigonal – Ditrigonal Pyramidal Table 2. Additional hypothetical tourmaline end member species inferred from.

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Presentation on theme: "Tourmaline EOSC 220 – November 23, 2004. Trigonal – Ditrigonal Pyramidal Table 2. Additional hypothetical tourmaline end member species inferred from."— Presentation transcript:

1 Tourmaline EOSC 220 – November 23, 2004

2 Trigonal – Ditrigonal Pyramidal Table 2. Additional hypothetical tourmaline end member species inferred from probable site occupancies (not currently recognized by IMA) Species (hypoth etical) (X)(Y 3 )(Z 6 )T 6 O 18 (BO 3 ) 3 V3V3 W Alkali tourmaline **These endmembers are theoretically possible, but not likely due to X-site vacancy - F avoidance that appears to take place in tourmaline.

3 Hardness (Mohs) 7 to 7.5 Specific Gravity 3.06 (+ 0.20; ) Crystal System Hexagonal-trigonal Colors Any and all. Tourmaline occurs in more colors than any other gem. Some colors have specific variety names, including: Bi-color: More than one color in the same stone Chrome: Intense green, colored by chromium and/or vanadium Indicolite: Blue Paraíba: Electric blue to green, colored by copper Rubellite: Red Watermelon: Pink in the center, green at the edge Pleochroism Strongly dichroic with the ordinary ray having a darker color Dispersion Phenomena Cat's eye tourmalines are common. Color-change chrome tourmalines, which change from green to red, are occasionally found. Tourmaline Group

4 Tourmaline Groups

5 Table 1. Current tourmaline end member species accepted by IMA Species (X)(Y 3 )(Z 6 )T 6 O 18 (BO 3 ) 3 V3V3 W Alkali tourmaline Elbaite NaLi 1.5 Al 1.5 Al 6 Si 6 O 18 (BO 3 ) 3 (OH) 3 (OH) SchorlNaFe 2+ 3 Al 6 Si 6 O 18 (BO 3 ) 3 (OH) 3 (OH) DraviteNaMg 3 Al 6 Si 6 O 18 (BO 3 ) 3 (OH) 3 (OH) Olenite*NaAl 3 Al 6 Si 6 O 18 (BO 3 ) 3 (O) 3 (OH) Chromd ravite NaMg 3 Cr 6 Si 6 O 18 (BO 3 ) 3 (OH) 3 (OH) Buergeri te NaFe 3+ 3 Al 6 Si 6 O 18 (BO 3 ) 3 (O) 3 F Povondr aite* NaFe 3+ 3 Fe 3+ 4 Mg 2 Si 6 O 18 (BO 3 ) 3 (OH) 3 O Vanadiu mdravite NaMg 3 V6V6 Si 6 O 18 (BO 3 ) 3 (OH) 3 (OH) Calcic tourmaline Liddicoa tite* CaLi 2 AlAl 6 Si 6 O 18 (BO 3 ) 3 (OH) 3 F Uvite*CaMg 3 MgAl 5 Si 6 O 18 (BO 3 ) 3 (OH) 3 F Hydroxy - feruvite* CaFe 2+ 3 MgAl 5 Si 6 O 18 (BO 3 ) 3 (OH) 3 (OH) X-site vacant tourmaline Rossma nite  LiAl 2 Al 6 Si 6 O 18 (BO 3 ) 3 (OH) 3 (OH) Foitite*  Fe 2+ 2 AlAl 6 Si 6 O 18 (BO 3 ) 3 (OH) 3 (OH) Magnesi ofoitite  Mg 2 AlAl 6 Si 6 O 18 (BO 3 ) 3 (OH) 3 (OH) * These end-members are modified from the original suggested formulae to produce proper end-members (Hawthorne and Henry, 1999).

6 Buergerite NaFe +3 Al 6 (BO 3 ) 3 Si 6 O 21 F in cavities in a rhyolite Bronze, Dark brown, Black From near Mexquitic, San Luis Potosi, Mexico

7 Chromdravite NaMg 3 (Cr,Fe +3 ) 6 (BO 3 ) 3 Si 6 O 18 (OH) 4 Greenish black, Dark green Onega trough, Karelia Republic, Northern Region, Russia

8 Dravite NaMg 3 Al 6 (BO 3 ) 3 Si 6 O 18 (OH) 4 Metasomatically altered magnesian or dolomitic limestones in contact-metamorphic aureoles Black, Green, Red, Blue, White Drava River, Austria

9 Feruvite (Ca,Na)(Fe,Mg,Ti) 3 (Al, Mg,Fe) 6 (BO 3 ) 3 Si 6 O 18 ( OH) 4 Brownish black, Dark brown, Black Repanga Island (Cuvier Island), Waikato, North Island, New Zealand

10 Foitite Na <0.5 (Fe +2,Al) 3 Al 6 Si 6 O 18 (BO 3 ) 3 (OH) 4 Bluish black California

11 Liddicoatite Ca(Li,Al) 3 Al 6 (BO 3 ) 3 Si 6 O 18 (O,OH,F) 4 Blue, Brown, Green, Pink, Red Detrital in soil, product of pegmatites From Antsirabe, Tsilaizina, and Anjanabonoina, Madagascar

12 Olenite NaAl 3 Al 6 (BO 3 ) 3 (Si 6 O 18 )(O,OH) 4 Light pink Aluminum-rich tourmaline. Forms a series with elbaite Decembrist pegmatite field, Olenik River Basin, Russia

13 Povondraite (Na,K)(Fe +3,Fe +2 ) 3 (Fe, Mg,Al) 6 (BO 3 ) 3 Si 6 O 18 (O H) 4 Black Alto Chapare district, Chapare Province, Cochabamba, Bolivia

14 Schorl NaFe +3 Al 6 (BO 3 ) 3 Si 6 O 1 8 (OH) 4 Black, Brownish black, Greenish black, Bluish black Granites, diorites, gabbro pegmatites, greisens, skarns and quartz veins Sonnenberg, Bodenmais and Spessart, Germany

15 Uvite (Ca,Na)(Mg,Fe +2 ) 3 Al 5 Mg(BO 3 ) 3 Si 6 O 18 (O H,F) 4 Yellowish brown, Brown, Blackish brown, Bluish black Pegmatitic and skarn rocks Province Uva, Sri Lanka

16 Vanadiumdravite NaMg 3 V 6 (Si 6 O 18 )(BO 3 ) 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

17 Elbaite Na(Li,Al) 3 Al 6 (BO 3 ) 3 Si 6 O 18 (OH) 4 Blue, Colorless, Green, Yellow, White Granitic pegmatites characterized by hydrothermal replacement Island of Elba, Italy

18 Elbaite

19

20 Watermelon Tourmaline

21 Cat’s Eye Tourmaline

22 Tourmalinated Quartz

23 Canadian - Stargazer

24 Canadian – Leduc, Quebec

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