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Konnert, Judith and Marta Flohr, 1992, unpublished data, USGS Reston, VA.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

av gr sz 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: 1_2_3_4_

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 ____ 0.2-3.0µm 200 g.s.=

LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=