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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: Adularia GDS57 Orthoclase DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS57

MINERAL_TYPE: Tectosilicate

MINERAL: Adularia (Orthoclase)(Feldspar group)

FORMULA: KAlSi3O8

FORMULA_HTML: KAlSi3O8

COLLECTION_LOCALITY: Floestenthal Tyrol, Austria

ORIGINAL_DONOR: Colorado School of Mines

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

K-feldspar commonly found in psuedo-orthorhombic crystals. It occurs mainly in low-temperature veins in gneisses and schists.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Feldspar of orthoclase subgroup.

Konnert, Judith and Marta Flohr, 1992, unpublished data, USGS Reston, VA.

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

None

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Bimodal grain size distribution:

population 1 = 650µm 99 vol%
population 2 = 40µm 1 vol%

avg. grain size of populations = 648µm

Smaller grains cover 20% of larger tabular grains. Grains have low relief, first order gray interference color, no visible twins, refractive index close to 1.51 oil. This sample was ground from a single k-feldspar crystal. 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 84 0.2-3.0µm 200 g.s.= 648 µm
LIB_SPECTRA: splib05a r 131 0.2-3.0µm 200 g.s.=


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