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Clark et. al. 2003 USGS Open File Report 03-395
Spectral Library splib05a Sample Description

(For further information on spectrsocopy, see: http://speclab.cr.usgs.gov)

TITLE: Augite NMNH120049 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: NMNH120049

MINERAL_TYPE: Inosilicate

MINERAL: Augite (Pyroxene group)

FORMULA: (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6

FORMULA_HTML: (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6

COLLECTION_LOCALITY: Rozier (nr.), Gorges du Tarn, Tarn, France

ORIGINAL_DONOR: National Museum of Natural History (Smithsonian)

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Diopside and hedenbergite form a complete solid solution series with physical and optical properties varying linearly with composition. Augite is a clinopyroxene in which some Na substitutes for Ca, some Al substitutes for both Mg (or Fe) and Si, and in which Fe and Mg
contents are higher than in diopside or hedenbergite.

"Results of petrographic examination: One 22.31g. piece, black, probably part of one crystal; some veining with lighter mineral (serpentine?) difficult to remove. Microscopic examination of hand-picked sample indicates about 1-2% contamination by low-index, iron stained mineral. Cleavage is virtually nonexistent, however, index of refraction and 2V point to augite."

Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Augite + dolomite (m). (Norma Vergo)

Sample is augite plus a moderate amount of dolomite. Sample subsequently treated with warm HCl to remove dolomite.

Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: EM(WDS) # XRF, EM(WDS), ICP(Trace), WChem


COMPOSITION
KEYWORD
Oxide
ASCII
Amount Weight
Percent, %
Oxide
html
COMPOSITION: SiO2 48.93 wt% SiO2
COMPOSITION: TiO2 1.38 wt% TiO2
COMPOSITION: Al2O3 8.44 wt% Al2O3
COMPOSITION: FeO 8.59 wt% FeO
COMPOSITION: MnO 0.21 wt% MnO
COMPOSITION: MgO 14.37 wt% MgO
COMPOSITION: CaO 16.87 wt% CaO
COMPOSITION: Na2O 1.57 wt% Na2O
COMPOSITION: K2O 0.02 wt% K2O
COMPOSITION: Total 100.38 wt%
COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S
COMPOSITION: New Total wt%

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

Average of 10 samples.

"Microprobe analysis shows the sample to be homogenous within and between grains. Sample could be classified as "ferroan augite". It has relatively high aluminum, iron and soda, and low calcium. Analysis indicates WO34, EN45, FS21 composition."

Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

"Microscopic examination of hand-picked sample indicates about 1-2% contamination by low-index, iron stained mineral. Cleavage is virtually nonexistent, however, index of refraction and 2V point to augite."

Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

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

LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment
LIB_SPECTRA: splib04a r 594 0.2-3.0µm 200 g.s.= 35 µm
LIB_SPECTRA: splib05a r 1238 0.2-3.0µm 200 g.s.=


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