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: Nephrite HS296 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS296.1B, HS296.3B, HS296.4B

MINERAL_TYPE: Inosilicate

MINERAL: Nephrite (Jade, Actinolite, Amphibole group)

FORMULA: Ca2(Mg,Fe+2)5Si8O22(OH)2

FORMULA_HTML: Ca₂(Mg,Fe⁺²)₅Si₈O₂₂(OH)₂

COLLECTION_LOCALITY: British Columbia

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

"I-19 Nephrite 296B--British Columbia: Nephrite is a tough compact variety of either tremolite or actinolite, which is used as the second source of gem quality jade (see inosilicate, I-9 for other source, jadeite). This sample contains magnetite as an impurity, which contributes to its low reflectivity, but the ferric and ferrous features are still apparent at 0.7µ and 1.0µ, as is the accompanying fall off to the blue. The hydroxyl features are quite evident at 1.4µ and 2.33µ with a small feature at 1.9µ indicating including water."

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.

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

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.5-9.5 keV
File: neph296.out, -.mdi
References: JCPDS # 13-347; Huebner's reference patterns
Found: chlorite, Ca-amphibole, unindexed weak reflection at 1.804 Angstroms.

Comment: Some strong chlorite basal intensities present, but the (001) and (003) are weak. Fairly well crystallized tremolite is observed with a very good match to the JCPDS pattern.

J.S.Huebner, J. Pickrell, T. Schaefer, written communication(USGS 1994)

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

None

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1c2_3_4_ # HS296.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2c3b4_ # HS296.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS296.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns