1 Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China;
2 Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, 20015 Washington, DC, USA

Xieite, a new mineral, occurs in the shock vein of the Suizhou meteorite. The mineral has an orthorhombic structure and its space group is Bbmm. The cell parameters are a = 9.462(6) Å, b = 9.562(9) Å, c = 2.916(1)Å. The crystal-chemical formula is (Fe_0.87Mg_0.13Mn_0.01)_1.01(Cr_1.62Al_0.25Ti_0.08V_0.02)_1.97O₄, or simply formula FeCr₂O₄. Stronger X-ray diffraction lines are [d (Å), I/I_o]: (2.675, 100), (2.389, 20), (2.089, 10), (1.953, 90), (1.566, 60), (1.439, 15), (1.425, 15), (1.337, 40). Xieite is a high pressure polymorph of FeCr₂O₄ and formed by solid-state transformation of chromite under shock-induced high pressure and temperature, in association with other high-pressure minerals including ringwoodite, majorite, lingunite and tuite. The P-T condition for the formation of xieite is estimated to be 18―23 GPa and 1800―1950℃, respectively. Xieite has recently been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA 2007-056). The mineral name, xieite, is named after Xiande Xie.

Supported by National Natural Science Foundation of China (Grant Nos. 40672035 and 40272028), and the Chinese Academy of Sciences (Grant No. KJCX2-SW-N20)