Clark and others 2007 USGS Data Series 231
Spectral Library splib06a Sample Description

(For further information on spectroscopy, 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.

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Andradite + Quartz - by Norma Vergo

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: 1b2b3b4b # 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.=
LIB_SPECTRA:	splib06a r 2203			g.s.=
LIB_SPECTRA:	splib06a r 2215			g.s.=