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Published July 2011 | public
Journal Article

Yttriaite-(Y): The natural occurrence of Y_(2)O_(3) from the Bol'shaya Pol'ya River, Subpolar Urals, Russia

Abstract

Yttriaite-(Y), ideally Y_(2_O_(3), is a new mineral (IMA2010-039) from the alluvial deposits of the Bol'shaya Pol'ya River, Subpolar Urals, Russia. The new mineral occurs as isolated crystals, typically cubo-octahedra <6 µm in size, embedded in massive native tungsten. Associated minerals include: copper, zircon, osmium, gold, and pyrite. The main forms observed are {100} and {111}. Due to the crystal size, physical properties could not be determined; however, the properties of synthetic Y_(2)O_(3) are well known. Synthetic Y_(2)O_(3) crystals are colorless to white with a white streak; crystals are transparent with an adamantine luster, while massive Y2O3 is typically translucent with an earthy luster. Synthetic Y_(2)O_(3) has a Vickers hardness of 653.91, which corresponds to 5.5 on the Mohs scale. Synthetic Y_(2)O_(3) crystals have good cleavage on {111}. Yttriaite-(Y) is isotropic; the refractive index measured at 587 nm on synthetic Y_(2)O_(3) is n = 1.931. The empirical chemical formula (mean of 4 electron microprobe analyses) calculated on the basis of 3 O is: Y_(1.98)Dy_(0.01)Yb_(0.01O3). Yttriaite-(Y) is cubic, space group Ia3(overbar), with parameters a = 10.6018(7) Å, V = 1191.62(7) Å3, and Z = 16. The five strongest lines in the powder X-ray diffraction pattern (measured on synthetic Y_(2)O_(3) using synchrotron radiation) are [d_obs in Å (I) (hkl)]: 3.0646 (100) (222), 1.8746 (55) (440), 1.5984 (38) (622), 2.6537 (26) (400), and 4.3356 (14) (211). The mineral name is based on the common name for the chemical compound, yttria.

Additional Information

© 2011 Mineralogical Society of America. Manuscript received November 14, 2010; manuscript accepted February 1, 2011; manuscript handled by Fernando Colombo. Associate Editor Fernando Colombo, referee Igor Pekov, and an anonymous reviewer provided helpful comments on the manuscript, which are greatly appreciated. NSERC Canada is thanked for a Discovery Grant to M.R. Parts of this study were funded by the John Jago Trelawney Endowment to the Mineral Sciences Department of the Natural History Museum of Los Angeles County and the White Rose Foundation at Caltech. The collection of synchrotron data was undertaken at the Australian National Beamline Facility with support from the Australian Synchrotron Research Program, which is funded by the Commonwealth of Australia under the Major National Research Facilities Program. SEM–EBSD analysis was carried out at the Caltech Geological and Planetary Sciences Division Analytical Facility, which is supported in part by NSF Grant EAR-0318518 and the NSF MRSEC Program under grant DMR-00800065. Lynn Boatner (Oak Ridge National Laboratory) is thanked for donation of the synthetic Y2O3 crystal standards. Jose Ygnacio Pastor (Universidad Politécnica de Madrid) is thanked for providing a specimen of synthetic W+Y2O3 for further study.

Additional details

Created:
August 22, 2023
Modified:
October 23, 2023