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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: Tremolite HS18 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS18.1B, HS18.2B, HS18.3, HS18.3B, HS18.4B

MINERAL_TYPE: Inosilicate

MINERAL: Tremolite (Amphibole group)

FORMULA: Ca2Mg5Si8O22(OH)2

FORMULA_HTML: Ca2Mg5Si8O22(OH)2

COLLECTION_LOCALITY: St. Lawrence County, New York

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 Actinolite and Ferroactinolite.

"S-1A. Amphibole, variety Tremolite. St. Lawrence Co., N.Y. (18B). This sample has a fairly prominent broad band near 1µ, indicating that it contains some ferrous ion. It displays a very sharp band at 1.4µ, and less sharp bands between 2.0 and 2.5 µ due to the overtone and combination tones of the OH stretch, respectively. In particular, the bands at 2.2 and 2.3 µ are due to combination tones of the OH stretch with lattice modes. The weak band at 1.9µ is probably due to a small amount of molecular H2O in the sample."

Hunt, G.R., J.W. Salisbury, 1970, Visible and near-infrared spectra of minerals and rocks: I. Silicate minerals. Modern Geology, v. 1, p. 283-300.

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:

Tremolite + medium amount quartz + small amount of mica + large amount of others; M: ~1% magnetite, no other minerals visible (Norma Vergo)

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: EPMA # XRF, EPMA, ICP(Trace), WChem

COMPOSITION
KEYWORD
Oxide
ASCII
Amount Weight
Percent, %
Oxide
html
COMPOSITION: SiO2 57.70 wt% SiO2
COMPOSITION: TiO2 0.05 wt% TiO2
COMPOSITION: Al2O3 1.00 wt% Al2O3
COMPOSITION: FeO 0.34 wt% FeO
COMPOSITION: MnO 0.33 wt% MnO
COMPOSITION: MgO 24.45 wt% MgO
COMPOSITION: CaO 12.26 wt% CaO
COMPOSITION: Na2O 0.51 wt% Na2O
COMPOSITION: K2O 0.15 wt% K2O
COMPOSITION: Total 97.79 wt%

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

Average of 6 analyses.
XFe+2 = 0.0083
XFe+3 = 0.0083
XMg+2 = 0.9924
XFetot = 0.0151

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1c2_3_4_ # HS18.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS18.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS18.3 # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2c3c4c # HS18.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS18.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns