Hydroxyferroromeite, a new secondary weathering mineral from Oms, France

作者：Mills Stuart J^*; Christya Andrew G; Rumsey Mike S; Spratt John; Bittarello Erica; Favreau Georges; Ciriotti Marco E; Berbain Christian

来源：European Journal of Mineralogy, 2017, 29(2): 307-314.

DOI：10.1127/ejm/2017/0029-2594

• hydroxyferroromeite
• pyrochlore
• romeite
• new mineral
• X-ray photoelectron spectroscopy
• antimonate

Hydroxyferroromeite, ideally (Fe-1.5(2+)square(0.5)) Sb25+O6(OII), is a new secondary mineral from the Correc d'en Llinassos, Oms, Pyrenees-Orientales Department, France. Hydroxyferroromeite occurs as yellow to yellow-brown powdery boxwork replacements up to about 50 mu m across after tetrahedrite in a siderite-quartz matrix. Nodistinct crystals have been observed. The empirical formula (based on 7 (O+OH) per formula unit, pfu) is (Fe1.072+Cu0.502+Zn0.03Sr0.03Ca0.01 square(0.36))(Sigma 2)(Sb1.885+Si0.09Al0.02As0.01)(Sigma 2)O-6((OH)(0.86)O-0.14). X-ray photoelectron spectroscopy was used to determine the valence states of Sb, Fe and Cu. Hydroxyferroromeite crystallises in the space group Fd (3) over barm with the pyrochlore structure and hence is a new Fe2+-dominant member of the romeite group of the pyrochlore supergroup. It has the unit-cell parameters: a=10.25(3)angstrom, V = 1077(6)angstrom(3) and Z = 8. A model, based on bond-valence theory, for incorporation of the small Fe2+ cation into a displaced variant of the A site of the pyrochlore structure is proposed.

• 出版日期2017-4