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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: Hectorite SHCa-1 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: SHCa-1

MINERAL_TYPE: Phyllosilicate

MINERAL: Hectorite (Montmorillonite group)

FORMULA: Na0.33(Mg,Li)3Si4O10(F,OH)2

FORMULA_HTML: Na0.33(Mg,Li)3Si4O10(F,OH)2

COLLECTION_LOCALITY: San Bernadino, California

ORIGINAL_DONOR: Grim Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Trioctahedral lithium montmorillonite (stored in H20).

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Hectorite + quartz (m) + calcite (L) + dolomite (s)? (Norma Vergo)

END_XRD_ANALYSIS.

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

COMPOSITION
KEYWORD
Oxide
ASCII
Amount Weight
Percent, %
Oxide
html
COMPOSITION: SiO2 34.7 wt% SiO2
COMPOSITION: TiO2 0.038 wt% TiO2
COMPOSITION: Al2O3 0.69 wt% Al2O3
COMPOSITION: Fe2O3 0.02 wt% Fe2O3
COMPOSITION: FeO 0.25 wt% FeO
COMPOSITION: MnO 0.008 wt% MnO
COMPOSITION: MgO 15.3 wt% MgO
COMPOSITION: CaO 23.4 wt% CaO
COMPOSITION: Li2O 2.18 wt% Li2O
COMPOSITION: Na2O 1.26 wt% Na2O
COMPOSITION: K2O 0.13 wt% K2O
COMPOSITION: P2O5 0.014 wt% P2O5
COMPOSITION: F 2.60 wt% F
COMPOSITION: F 2.75 wt% F
COMPOSITION: S 0.01 wt% S
COMPOSITION: LOI 21.80 wt% LOI
COMPOSITION: Total 99.80 wt%
COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S
COMPOSITION: New Total wt%

COMPOSITION_TRACE:

None

COMPOSITION_DISCUSSION:

None

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Mode:
99 vol% hectorite
1 vol% quartz
trace opaques (metallic luster)

Bimodal Grain Size Distribution:
mode 1: 204 µm @ 80 vol%
mode 2: 25 µm @ 20 vol%

average grain size = 183 µm

Clay grains have sweeping extinction, quartz present but no evidence of calcite or dolomite. All consistent with a fairly pure sample of hectorite. G. Swayze.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1c2_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 1974 0.2-3.0µm 200 g.s.= 183 µm
LIB_SPECTRA: splib04a r 1985 0.2-3.0µm 200 g.s.= 183 µm
LIB_SPECTRA: splib05a r 3112 0.2-3.0µm 200 g.s.=


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