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: Serpentine HS318 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS318.1B, HS318.2B, HS318.3B, HS318.4B, HS318.6

MINERAL_TYPE: Phyllosilicate

MINERAL: Serpentine

FORMULA: Mg3Si2O5(OH)4

FORMULA_HTML: Mg₃Si₂O₅(OH)₄

COLLECTION_LOCALITY: Colorado

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

"P-11 Serpentine 318B--Colorado. Mg₃(Si₂O₅)- (OH)₄: The principal occurrences of serpentine are those in which they are derived by alteration of ultrabasic rocks. Serpentine specimens, like talc, deviate little from the ideal composition. However, also like talc, small amounts of aluminum and iron may replace silicon and magnesium. This particular sample is burdened with magnetite contamination, but still displays ferric ion bands at 0.65 and 0.45µ as well as clearly visible OH features at 1.4µ and 2.34µ. This latter feature is attributed to a combination of the OH stretch with the Mg-OH bend."

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
.2B = <74 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: serpn318.out, -.mdi (edge/random mount)
References: S.W. Bailey (1988, Clays and Clay Minerals 36, 193-213); FJWicks and DS O'Hanley (1988, MSA Reviews in Mineralogy 19, 91-167; JCPDS #11-386; Huebner's reference patterns.
Found: lizardite, minor chlorite, many unidentified but weak reflections

Comment: Excellent match to the JCPDS pattern. Strong pattern with some peak broadening. A member of Bailey's group C serpentines; probable 6T polytype of Wicks and O'Hanley, but with some discrepant intensities. The pattern is more complex than that of a 1T serpentine polytype.

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:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1c2_3_4_ # HS318.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS318.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS318.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS318.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS318.6 # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns