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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: Andradite HS111 Garnet DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS111

MINERAL_TYPE: Nesosilicate

MINERAL: Andradite (Garnet group)

FORMULA: Ca3(Fe+3)2(SiO4)3

FORMULA_HTML: Ca3Fe+32(SiO4)3

COLLECTION_LOCALITY: Graham County, Arizona

ORIGINAL_DONOR: Wards Scientific

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms series with Grossular and with Schorlomite.

Under a hand lens the sample appears brown. Individual grains have varying shades of brown with an overall "salt and pepper" effect. The visible and near-IR spectrum shows spectrally pure andradite.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Andradite + Quartz - by Norma Vero

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

None

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Optical examination gives the following mineral mode:

85 vol% andradite
15 vol% Fe-stained mineral or andradite

avg. grain size = 270µm

Conchoidally fractured andradite grains some of which are partially Fe-stain coated. Entire grains Fe-stained may be different phase or andradite. G. Swayze

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 378 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 986 0.2-3.0µm 200 g.s.=


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