Skip to main content Accessibility help

Mushroom elbaite from the Kat Chay mine, Momeik, near Mogok, Myanmar: II. Zoning and crystal growth

  • A. J. Lussier (a1), F. C. Hawthorne (a1), S. Herwig (a2), Y. Abdu (a1), P. M. Aguiar (a2), V. K. Michaelis (a2) and S. Kroeker (a2)...


A variety of mushroom tourmaline from the Kat Chay mine, Momeik, near Mogok, Shan state, Myanmar, consists of a black-to-grey single-crystal core from which a single prismatic crystal reaches to the edge of the mushroom, forming a slight protuberance. The rest of the mushroom (∼50% by volume) consists of extremely acicular sub-parallel crystals that diverge toward the edge of the mushroom. The acicular crystals are dominantly colourless to white, with a continuous black zone (2 mm across) near the edge, and pale pink outside the black zone. The composition varies from ∼Na0.75Ca0.05(Li0.80Al0.70Fe1.10.Mn0.30Ti0.10)Al6Si6(B03)3O18(OH)3(OH,F) at the base of the mushroom to ∼Na0.60Ca0.06(Li1.00Al1.98Fe0.02)Al6(Si5.35B0.65)(BO3)3O18(OH)3(OH,F) close to the edge at the top of the mushroom. The principal substitutions are: (1) YLi + YAl -> yFe* + yFe* and (2) TB + yAl -> Si + yFe*, but there are five other minor substitutions that are also operative. There are six significant compositional discontinuities at textural boundaries in the mushroom, suggesting that the changes in habit are driven in part by changes in external variables such as T and P, plus possible involvement of new fluid phases.


Corresponding author


Hide All
Bloodaxe, E.S., Hughes, J.M., Dyar, M.D., Grew, E.S. and Guidotti, C.V. (1999) Linking structure and chemistry in the schorl-dravite series. American Mineralogist, 84, 922928.
Cempírek, J., Novak, M., Ertl, A., Hughes, J.M., Rossman, G.R. and Dyar, M.D. (2006) Fe-bearing olenite with tetrahedrally coordinated Al from an abyssal pegmatite at Kutna Hora, Czech Republic: structure, crystal chemistry, optical and XANES spectra. The Canadian Mineralogist, 44, 2330.
Dutrow, B.L. and Henry, DJ. (2000) Complexly zoned fibrous tourmaline, Cruzeiro Mine, Minas Gerais, Brazil: a record of evolving magmatic and hydro-thermal fluids. The Canadian Mineralogist, 38, 131143.
Ertl, A. and Hughes, J.M. (2002) The crystal structure of an aluminum-rich schorl overgrown by boron-rich olenite from Koralpe, Styria, Austria. Mineralogy and Petrology, 75, 6978.
Ertl, A., Pertlik, F. and Berhardt, H.-J. (1997) Investigations on olenite with excess boron from the Koralpe, Styria, Austria. Anzeiger, 134, 310.
Ertl, A., Hughes, J.M., Brandstatter, F., Dyar, M.D. and Prasad, P.S.R. (2003) Disordered Mg-bearing olenite from a granitic pegmatite from Goslarn, Austria: A chemical, structural and infrared spectroscopic study. The Canadian Mineralogist, 41, 13631370.
Ertl, A., Rossman, G.R., Hughes, J.M., Prowatke, S. and Ludwig, T. (2005) Mn-bearing “oxy-rossmanite” with tetrahedrally coordinated Al and B from Austria: structure, chemistry, and infrared and optical spectroscopy. American Mineralogist, 90, 481487.
Ertl, A., Hughes, J.M., Prowatke, S., Ludwig, T., Prasad, P.S.R., Brandstatter, F., Korner, W., Schuster, R., Pertlik, F. and Marschall, H. (2006) Tetrahedrally coordinated boron in tourmalines from the liddicoatite-elbaite series from Madagascar: structure, chemistry, and infrared spectroscopic studies. American Mineralogist, 91, 18471856.
Ertl, A., Hughes, J.M., Prowatke, S., Ludwig, T., Brandstatter, F., Korner, W. and Dyar, M.D. (2007) Tetrahedrally coordinated boron in Li-bearing olenite from ‘Mushroom’ tourmaline from Momeik, Myanmar. The Canadian Mineralogist, 45, 891899.
Federico, M., Andreozzi, G.B., Lucchesi, S. and Graziani, G. (1998) Compositional variation of tourmaline in the granitic pegmatite dykes of the Cruziero mine, Minas Gerais, Brazil. The Canadian Mineralogist, 36, 415431.
Foord, E.E., Starkey, H.C. and Taggert, J.E. Jr. (1986) Mineralogy and paragenesis of ‘pocket’ clays and associated minerals in complex granitic pegmatites, San Diego County, California. American Mineralogist, 71, 428439.
Hughes, J.M., Ertl, A., Dyar, M.D., Grew, E.S., Shearer, C.K., Yates, M.G. and Guidotti, C.V. (2000) Tetrahedrally coordinated boron in tourmaline: boron-rich olenite from Stoffhutte, Koralpe, Austria. The Canadian Mineralogist, 38, 861868.
Hughes, K.-A., Hughes, J.M. and Dyar, M.D. (2001) Chemical and structural evidence for [4]B ⟺ [4]Si substitution in natural tourmalines. European Journal of Mineralogy, 13, 743747.
Hughes, J.M., Ertl, A., Dyar, M.D., Grew, E.S., Wieden-Beck, M. and Brandstatter, F. (2004) Structural and chemical response to varying [4]B content in zoned Fe-bearing olenite from Koralpe, Austria. American Mineralogist, 89, 447454.
Jolliff, B.L., Papike, JJ. and Shearer, C.K. (1986) Tourmaline as a recorder of pegmatite evolution: Bob Ingersoll pegmatite, Black Hills, South Dakota. American Mineralogist, 71, 472500.
Kalt, A., Schreyer, W., Ludwig, T., Prowatke, S., Bernhardt, H.-J. and Ertl, A. (2001) Complete solid solution between magnesian schorl and lithian excess-boron olenite in a pegmatite from the Koralpe (eastern Alps, Austria). European Journal of Mineralogy, 13, 11911205.
London, D. (1986) Formation of tourmaline-rich gem pockets in miarolitic pegmatites. American Mineralogist, 71, 396405.
London, D. (1999) Stability of tourmaline in peraluminous granite systems: the boron cycle from anatexis to hydrothermal aureoles. European Journal of Mineralogy, 11, 253262.
London, D. and Manning, D.A.C. (1995) Chemical variation and significance of tourmaline from Southwest England. Economic Geology, 90, 495519.
Lussier, A.J., Aguiar, P.M., Michaelis, V.K, Kroeker, S., Herwig, S., Abdu, Y. and Hawthorne, F.C. (2008) Mushroom elbaite from the Kat Chay mine, Momeik, near Mogok, Myanmar: I. Crystal chemistry by SREF, EMPA, MAS NMR and Mössbauer spectroscopy. Mineralogical Magazine, 72, 747761.
Lussier, A.J., Aguiar, P., Michaelis, V., Kroeker, S. and Hawthorne, F.C. (2009) The occurrence of tetrahedrally coordinated Al and B in tourmaline: A 11B and 27Al MAS NMR study. American Mineralogist, (in press).
Macdonald, DJ. and Hawthorne, F.C. (1995) The crystal chemistry of Si-Al substitution in tourmaline. The Canadian Mineralogist, 33, 849858.
Marler, B. and Ertl, A. (2002) Nuclear magnetic resonance and infrared spectroscopic study of excess-boron olenite from Koralpe, Styria, Austria. American Mineralogist, 87, 364367.
Marler, B., Borowski, M., Wodara, U. and Schreyer, W. (2002) Synthetic tourmaline (olenite) with excess boron replacing silicon in the tetrahedral site: II. Structure analysis. European Journal of Mineralogy, 14, 763771.
Prowatke, S., Ertl, A. and Hughes, J.M. (2003) Tetrahedrally-coordinated Al in Mn-rich, Li- and Fe-bearing olenite from Eibenstein an der Thaya, Lower Austria: A chemical and structural investigation. Neues Jahrbuch fur Mineralogie, Monatshefte, 2003, 385395.
Schreyer, W., Wodara, U., Marler, B., van Aken, P.A., Seifert, F. and Robert, J.-L. (2000) Synthetic tourmaline (olenite) with excess boron replacing silicon in the tetrahedral site: I. Synthesis conditions, chemical and spectroscopic evidence. European Journal of Mineralogy, 12, 529541.
Schreyer, W., Hughes, J.M., Bernhardt, H.-J., Kalt, A., Prowatke, S. and Ertl, A. (2002) Reexamination of olenite from the type locality: detection of boron in tetrahedral coordination. European Journal of Mineralogy, 14, 935942.
Selway, J.B., Novàk, M., Černý, P. and Hawthorne, F.C. (1999) Compositional evolution of tourmaline in lepidolite-subtype pegmatites. European Journal of Mineralogy, 11, 569584.
Selway, J.B., Černý, P., Hawthorne, F.C. and Novàk, M. (2000) The Tanco pegmatite at Bernic Lake, Manitoba. XIV. Internal tourmaline. The Canadian Mineralogist, 38, 877891.
Selway, J.B., Smeds, S.-A., Černý, P. and Hawthorne, F.C. (2002) Compositional evolution of tourmaline in the petalite-subtype Nykopingsgruvan pegmatites, Utö, Stockholm Archipelago, Sweden. GFF, 124, 93102.
Tagg, S.L., Cho, H., Dyar, M.D. and Grew, E.S. (1999) Tetrahedral boron in naturally occurring tourmaline. American Mineralogist, 84, 14511455.
Vorbach, A. (1989) Experimental examinations on the stability of synthetic tourmalines in temperatures from 250°C to 750°C and pressures up to 4 kb. Neues Jahrbuch fur Mineralogie Abhandlung, 161, 6983.
Zaw, K (1998) Geological evolution of selected granitic pegmatites in Myanmar (Burma): constraints from regional setting, lithology, and fluid-inclusion studies. International Geology Review, 40, 647662.



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed