Arsenoflorencite-(Ce): A New Arsenate Mineral from Australia

E. H. Nickel and J. E. Temperly
Division of Minerals and Geochemistry, CSIRO, Private Bag PO, Wembley, WA, Australia 6014
CRA Exploration Pty Ltd, PO Box 175, Belmont, WA, Australia 6104

Abstract: Arsenoflorencite-(Ce) has been found at three localities in Australia—two in South Australia, and one in Queensland. It occurs as colourless to light brown scalenohedral crystals and crystal fragments in stream sediments. Electron microprobe analysis gave Ce2O3 12.97, La2O3 8.62, Pr2O3 3.35, Nd2O3 2.40, Gd2O3 1.38, Sm2O3 0.38, SrO 1.99, Al2O3 28.75, As2O5 27.02, P2O5 4.68, SO3 1.21%; calc, H2O 9.36%; total 102.11%. The simplified formula is REAl3(AsO4)2(OH)6, with Ce as the dominant RE element. Arsenoflorencite-(Ce) is rhombohedral, has space group R3m with αhex. 7.029 and chex. 16.517 Å, and Z = 3. Strongest X-ray powder diffraction lines are: 3.513(6)(110), 2.963(10)(113), 2.201(4)(107), 1.905(5)(303) and 1.753 Å(4)(220). Density is 4.096 (meas.) and 4.091 (calc.) g/cm3. Hardness is VHN10 170. Arsenoflorencite-(Ce) is brittle, breaks with a conchoidal fracture, and has no perceptible cleavage. The mineral is colourless in transmitted light, uniaxial positive, and has ω 1.739 and ɛ 1.745 (λ = 589 nm). Arsenoflorencite-(Ce) is the arsenate analogue of florencite-(Ce), and the name was chosen to indicate this relationship.

Keywords: arsenoflorencite-(Ce) • arsenates • florencite-(Ce) • new mineral • South Australia • Queensland • Australia

Mineralogical Magazine; October 1987 v. 51; no. 62; p. 605-609; DOI: 10.1180/minmag.1987.051.362.16
© 1987, The Mineralogical Society
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