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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
For more information on the library, see: local link web link

TITLE: Monticellite HS339 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS339.1B, HS339.2B, HS339.3B, HS339.4B

MINERAL_TYPE: Nesosilicate

MINERAL: Monticellite (Olivine group)

FORMULA: CaMgSiO4

FORMULA_HTML: CaMgSiO4

COLLECTION_LOCALITY: Texas

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms series with Kirschsteinite.

Original spectrum published in: Hunt, G.R., J.W. Salisbury, and C.J. Lenhoff, 1973, Visible and near-infrared spectra of minerals and rocks: VI. Additional silicates. Modern Geology, v. 4, p. 85-106.

With the comment:"This sample is spectrally quite featureless except for a very weak band near 1.0µm and weak features in the visible. Although monticellite typically shows remarkably small departures from ideal composition, it is obvious that a small amount of Fe2+ has substituted for the Mg, producing both the 1µm band and the fall off toward the blue in the visible."

Grain size fractions are indicated by the extension after the sample number:
.1B = <5 µm
.2B = <74 µm
.3B = 74-250 µm
.4B = 250-1200 µm

IMAGE_OF_SAMPLE:
Photo of sample

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.5-9.5 keV
References: JCPDS #35-590
Found: Monticellite; weak reflections at 5.6, 2.45, 1.56, 1.42 Angstroms

Comment: Monticellite is well crystallized.

J.S.Huebner, J.Pickrell, T. Schaefer,written communication(USGS)

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

None.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

Sharp spectral absorptions at 1.4, 2.24, and 2.32 microns are from trace contaminants that increase in abundance as the grain size of the monticellite increases being most intense in the HS339.4B sample. G. Swayze.

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2_3_4_ # HS339.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2_3_4_ # HS339.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2c3c4c # HS339.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS339.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns