Original paper

Tetrahedrally-coordinated Al in Mn-rich, Li- and Fe-bearing olenite from Eibenstein an der Thaya, Lower Austria: A chemical and structural investigation

Prowatke, Stefan; Ertl, Andreas; Hughes, John M.

Abstract

Chemical analysis (including light elements) of a Mn-rich tourmaline from a recently discovered locality near Eibenstein an der Thaya, Lower Austria, characterizes the sample as Mn-rich, Li-, and Fe-bearing olenite. Chemical analysis in combination with the crystal structure (a = 15.9325(5) Å, c = 7.1308(4) Å, R = 0.022) demonstrate that significant amounts of [4]Al (0.33 apfu) occur at the T site of this Mn-rich olenite, in very good agreement with the amount of [4]Al predicted by the <T-O> distance of ≈1.626 Å. Significant amounts of [4]Al are for the first time verified in Mn-rich olenite. Interestingly, the Li content with 0.79wt.% Li2O of this sample is relatively low for Mn-bearing tourmaline. The optimized formula (chemical data in combination with refinement of the site scattering) of this Mnrich, Li- and Fe-bearing olenite is X(Na0.827Ca0.022K0.0040.147) Y(Al1.349Mn0.676Li0.517Fe0.227Ti0.038Mg0.002Zn0.0020.189) ZAl6.00 B3.00 T(Si5.675Al0.325) O27[(OH)3.368F0.498O0.134].

Keywords

tourmalinemn-rich olenitetetrahedrally-coordinated aluminumt-o bond length