a new mineral from the tourmaline supergroup

Milan Novák1, Andreas Ertl2, Pavel Povondra3, Michaela Vašinová Galiová4, George R. Rossman5, Helmut Pristacz2, Markus Prem2, Gerald Giester2, Petr Gadas1 and Radek Škoda1

1Department of Geological Sciences, Masaryk University, Kotlářská 2, 611 37, Brno, Czech Republic

2Institut für Mineralogie und Kristallographie, Geozentrum, Universität Wien, Althanstrasse 14, A 1090 Wien, Austria

3Department of Geochemistry, Mineralogy and Natural Resources, Charles University, Albertov 6, 128 43 Praha 2, Czech Republic

4Department of Chemistry, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic

5Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125-2500, USA


Darrellhenryite, a new member of the tourmaline supergroup (relates to the alkali-subgroup 4), is a new Li-bearing tourmaline species derived from closely related elbaite by the substitution YAl0.5WO1 YLi-0.5W(OH)-1. It occurs in complex (Li-bearing) petalite-subtype pegmatite with common lepidolite, Li-bearing tourmalines, and amblygonite from Nová Ves near Český Krumlov, southern Bohemia, Moldanubian Zone, Czech Republic. This zoned pegmatite dike, crosscuts a serpentinite body enclosed in leucocratic granulites. Darrellhenryite forms columnar crystals (sometimes in parallel arrangement), up to 3 cm long and up 2 cm thick, associated with albite (cleavelandite), minor quartz, K-feldspar, petalite, rare polylithionite and locally rare pollucite. The optical properties and the single-crystal structure study (R1 = 0.019) of darrellhenryite confirm trigonal symmetry, ω = 1.636(2), ε = 1.619(2), birefringence: 0.017, space group R3m, a = 15.809(2), c = 7.089(1) Ĺ, V = 1534.4(4) Ĺ3, and Z = 3. The chemical analysis, in combination with the crystal structure refinement, gives the formula X(Na0.58Ca0.01˙0.41) Y(Li1.05Al1.95) ZAl6 (BO3)3 T(Si6O18) V(OH)3 W(O0.66F0.34), which can be simplified to an ideal formula of NaLiAl2Al6(BO3)3Si6O18(OH)3O. The strongest lines of the powder pattern [d in Ĺ (I, hkl)] are 4.180 (39, 211), 3.952 (54, 220), 3.431 (73, 012), 2.925 (100, 122), 2.555 (90, 051), 2.326 (42, 511), 2.029 (42, 223), 2.021 (42, 152), 1.901 (50, 342), 1.643 (49, 603). The density is Dmeas = 3.03(3) g/cm3, Dcalc = 3.038 g/cm3. Darrellhenryite is likely related to Li- and B-rich but F-moderate environments in complex pegmatites; no influence of higher activity of O on the darrellhenryite formation is implied from its mineral assemblage. The name is for Darrell J. Henry, Professor of Geology at the Louisiana State University, Baton Rouge, USA, an expert on the mineralogy, petrology, crystal chemistry and nomenclature of tourmaline-supergroup minerals.


A portion of the type darrellhenreyite. The pink color comes from its manganese content.

Optical Spectral Data:
    E perpendicular to c
    E parallel to c
    Image of the Vis    plotted as 1.0 mm.

Near-Infrared Data:
    E perpendicular to c
    E parallel to c  
    Image of the NIR    plotted as 1.0 mm.

last revised 23-Nov-2012