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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: Talc TL2702 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: TL2702

MINERAL_TYPE: Phyllosilicate

MINERAL: Talc

FORMULA: Mg3Si4O10(OH)2

FORMULA_HTML: Mg3Si4O10(OH)2

COLLECTION_LOCALITY: Colorado

ORIGINAL_DONOR: Colorado School of Mines

CURRENT_SAMPLE_LOCATION: CSES/CIRES, Univ. of CO, Boulder

ULTIMATE_SAMPLE_LOCATION: CSES/CIRES, Univ. of CO, Boulder

SAMPLE_DESCRIPTION:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Pure (?).

Kruse, F.A., and P.L. Hauff, eds., 1992, The IGCP-264 Spectral Properties Database. IUGS/UNESCO, Special Publication, 211 p., (in press).

40kV - 30mA, 6.5-9.5 keV
File: talc2702.mdi (smear on quartz plate)
References: JCPDS #3-0588, 19-0770, 29-1493
Found: Talc 2M
Sought but not found: willemsite, pyrophyllite

Comment: The (002), (004), and (006) basal reflections are sharp and intense, but the non-basal reflections are weak, broad, and adjacent peaks are not resolved. All pattern reflections can be indexed by comparison with the JCPDS talc 2M reference patterns #13-0558 or 19-0770.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: # XRF, EM(WDS), ICP(Trace), WChem

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Bimodal grain size distribution:
mode 1: 550 µm @ 90 vol%
mode 2: 15 µm @ 10 vol%

average grain size= 522 µm

Mottled extinction, very soft, no visible impurities, all consistent with this sample being talc. Smaller grains coat 30% surface of larger grains. 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 4708 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 6496 0.2-3.0µm 200 g.s.=


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