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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 WS592 Pyroxene DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: WS592

MINERAL_TYPE: Inosilicate

MINERAL: Augite (Pyroxene Group)(was listed as Diopside)

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

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

COLLECTION_LOCALITY: Klammath, OR

ORIGINAL_DONOR: Wards Mineral Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.7-9.5 keV
File: dipsd592_mdi
References: PDF2 #41-1370; Huebner's cell refinement for diopside, Rotkopschart, Zillertal, Austria
Found: Clinopyroxene

Comments: Very sharp peaks and excellent resolution of alpha1-alpha2 components indicate excellent crystallinity and compositional homogeneity. All observed reflections indexed can be diopside-rich clinopyroxene. Lattice spacing's are slightly smaller than HS-15, HS-119, and synthetic end member diopside. Profile-based search match returns aluminian augite (41-1370, 5.4 percent, Al2O3), which is an excellent visual match to WS-592. Unit cell dimensions are a=9.728(4), b=8.904(4), c=5.258(2) angstroms, and beta=106.39(4) degrees. These observations are consistent with diopsidic augite.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Bimodal grain size distribution:
population 1 size = 223 microns at 60 vol%
population 2 size = 40 microns at 40 vol%
avg gr sz = 174 µm

Trace magnetite. Two cleavages at nearly right angles, inclined extinction, slight pleochroism?, pale green color, high order color under cross-polarized light, biaxial (+). All consistent with augite. G. Swayze.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1a2_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 614 0.2-3.0µm 200 g.s.= 174 µm
LIB_SPECTRA: splib05a r 1262 0.2-3.0µm 200 g.s.=


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