Sample Description USGS Spectral Library Version 7

USGS Spectral Library Version 7 Sample Description

Kokaly, R.F., Clark, R.N., Swayze, G.A., Livo, K.E., Hoefen, T.M., Pearson, N.C., Wise, R.A., Benzel, W.M., Lowers, H.A., Driscoll, R.L., and Klein, A.J., 2017, USGS Spectral Library Version 7: U.S. Geological Survey Data Series 1035, 61 p., https://doi.org/10.3133/ds1035
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TITLE: Monazite_REE GDS957 New Mex DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS957

MINERAL_TYPE: Phosphate

MINERAL: Monazite

FORMULA: (Ce,La,Nd,Th)PO4

FORMULA_HTML: (Ce,La,Nd,Th)PO₄

COLLECTION_LOCALITY: Petaca district, New Mexico, USA

ORIGINAL_DONOR: Jim Post

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION: Light brown powder.

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

XRD analysis indicates sample is monazite, cheralite (a monazite group mineral with elevated Thorium), or huttonite. Apparently huttonite, with the chemical formula ThSiO₄, is isostructural and may form a continuous series with monazite. These three possibilities, monazite, cheralite, and huttonite have similar XRD patterns and are difficult to distinguish from one another. Sample also contains minor quartz and a presumed but unidentificed clay. (R. Driscoll)

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EPMA, ICP(Trace), WChem

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

There are numerous intense sharp absorptions (f-f orbital electronic transitions) throughout the 0.35 to 1.35 micron region presumably due to variable proportions of lanthanide series rare earth elements (i.e., Nd, Sm, and others). Bands at 0.580, 0.745, 0.800, and 0.871 microns resemble similar absorptions in neodymium oxide. (G. Swayze)

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2_3_4_ # GDS957 # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns