Volume 53, Number 21, 3341-3345, DOI: 10.1007/s11434-008-0407-1

Xieite, a new mineral of high-pressure FeCr2O4 polymorph

Ming Chen, JinFu Shu and Ho-kwang Mao

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Abstract

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 (Fe0.87Mg0.13Mn0.01)1.01(Cr1.62Al0.25Ti0.08V0.02)1.97O4, or simply formula FeCr2O4. Stronger X-ray diffraction lines are [d (Å), lll 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°C, 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.

Keywords  xieite - chromite - high-pressure - polymorph - new mineral - shock - Suizhou meteorite

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

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