Rameauite: Difference between revisions
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5 ^Cesbron, F., W.L. Brown, P. Bariand, and J. Geffroy (1972) Rameauite and agrinierite, two new hydrated complex uranyl oxides from Margnac, France. Mineral. Mag., 38, 781–789. |
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Revision as of 14:51, 29 October 2010
| Rameauite | |
|---|---|
| General | |
| Category | Oxide mineral |
| Formula (repeating unit) | K2Ca(UO2)6OH16·H2O or K2CaU6+6O20·9(H2O) |
| Crystal system | Monoclinic |
| Space group | Monoclinic |
| Unit cell | a= 13.97, b= 14.26, c= 14.22 Å, β = 121.02° |
| Identification | |
| Formula mass | 2,028.57 g |
| Color | Orange |
| Crystal habit | Prismatic and/or can consist of a hexagonal outline |
| Cleavage | Good cleavage |
| Diaphaneity | Semitransparent |
| Density | 5.6 |
| Optical properties | Biaxial Negative |
| Refractive index | a= n.d. β= 1.95 γ= 1.97 |
| 2V angle | 32° (meas.) |
| References | [1][2][3] |
Rameauite is a uranium oxide mineral with formula K2Ca(UO2)6OH16·H2O[4] or K2CaU6+6O20·9(H2O).[3]
It was first described in 1972 for an occurrence in the Margnac Mine, Compreignac, Haute-Vienne, Limousin, France and named for the French prospector who discovered the mine, Jacques Rameau.[4]
Rameauite occurs as small orange crystals with calcite and ex-uranophane on a block of pitchblende. They are all twinned on {100}, slightly flattened parallel to {010}, elongated parallel to [001], with a pseudo-hexagonal section. The observed forms are {010}, {100}, {001},and {110}; measured (100): (001) = 58°40', (010):(110) = 49° 50'. There is a good cleavage parallel to {010}. Rameauite is monoclinic pseudo-hexagonal with a= 13'97, b= 14'26, c= 14'22.[5]
References
5 ^Cesbron, F., W.L. Brown, P. Bariand, and J. Geffroy (1972) Rameauite and agrinierite, two new hydrated complex uranyl oxides from Margnac, France. Mineral. Mag., 38, 781–789.