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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 WS588 Pyroxene DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: WS558

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: Hull, Ontario, Canada

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: dipsd588_mdi (smear on qtz plate)
References: Borg and Smith (1969); PDF2 #41-1370, 24-0201; Huebner's reference patterns and cell refinements, particularly that of diopside from Rotkopschart, Zillertal, Austria
Found: Clinopyroxene

Comments: Peaks are moderately sharp to sharp but the alpha1-alpha2 components are not well resolved. The high background is probably due to X-ray fluorescence (suggesting (Fe and/or Mn are present). All reflections can be indexed as clinopyroxene.
Identification was confirmed with profile-based search-match (ferroan augite, 24-0201). Lattice spacing's are larger than those of WS-592, HS-15, or synthetic end member diopside, yet smaller than those of hedenbergite HS-10. Conclude that this material is a clinopyroxene solid solution, not an end member diopside.

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 grain size = 450 microns at 80 vol%
population 2 grain size = 15 microns at 20 vol%

avg. grain size = 400 microns

Pure sample, inclined extinction, two cleavages at nearly right angles, pale green color, high order colors under cross-polarized light, biaxial (+), weak pleochroism, all consistent with aguite. 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 604 0.2-3.0µm 200 g.s.= 400 µm
LIB_SPECTRA: splib05a r 1250 0.2-3.0µm 200 g.s.=


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