Publication Date:
2013-10-26
Description:
Deveroite-(Ce), ideally Ce 2 (C 2 O 4 ) 3 ·10H 2 O, is a new mineral (IMA 2013-003) found in the alpine fissures of Mount Cervandone, overlooking the Devero Valley, Piedmont, Italy. It occurs as sprays of colourless elongated tabular, acicular prisms only on cervandonite-(Ce). It has a white streak, a vitreous lustre, is not fluorescent and has a hardness of 2–2.5 (Mohs' scale). The tenacity is brittle and the crystals have a perfect cleavage along {010}. The calculated density is 2.352 g/cm 3 . Deveroite-(Ce) is biaxial (–) with 2V of ~77°, is not pleochroic and the extinction angle (β ^ c ) is ~27°. No twinning was observed. Electron microprobe analyses gave the following chemical formula: (Ce 1.01 Nd 0.33 La 0.32 Pr 0.11 Y 0.11 Sm 0.01 Pb 0.04 U 0.03 Th 0.01 Ca 0.04 ) 2.01 (C 2 O 4 ) 2.99 ·9.99H 2 O. Although synchrotron radiation was not used to solve the structure of deveroite-(Ce) the extremely small size of the sample (13 μm x 3 μm x 1 μm) did not allow us to obtain reliable structural data. However, it was possible to determine the space group (monoclinic, P 2 1 / c ) and the unit-cell parameters, which are: a = 11.240(8) Å, b = 9.635(11) Å, c = 10.339(12) Å, β = 114.41(10)°, V = 1019.6 Å 3 . The strongest lines in the powder diffraction pattern [ d in Å( I )( hkl )] are: 10.266(100)(100); 4.816(35.26)(211I); 3.415(27.83)(300); 5.125(24.70)(200); and 4.988(22.98)(111). Deveroite-(Ce) is named in recognition of Devero valley and Devero Natural Park.
Print ISSN:
0026-461X
Electronic ISSN:
1471-8022
Topics:
Geosciences
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