Sample Description USGS Spectral Library Version 7

USGS Spectral Library Version 7 Sample Description

Kokaly, R.F., Clark, R.N., Swayze, G.A., Livo, K.E., Hoefen, T.M., Pearson, N.C., Wise, R.A., Benzel, W.M., Lowers, H.A., Driscoll, R.L., and Klein, A.J., 2017, USGS Spectral Library Version 7: U.S. Geological Survey Data Series 1035, 61 p., https://doi.org/10.3133/ds1035
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TITLE: Desert_Varnish GDS78A DESCRIPT

DOCUMENTATION_FORMAT: MIXTURE

SAMPLE_ID: GDS78A

MIXTURE_TYPE: Coating

MIXTURE: Desert_Varnish

FORMULA: Na4Mn14O27*9H20 + alpha-Fe2O3 + clays

FORMULA_HTML: Na₄Mn₁₄O₂₇•9H₂ + alpha -Fe₂O₃

COLLECTION_LOCALITY: Stoddard Wells, CA.

ORIGINAL_DONOR: George Rossman, California Inst. of Technology

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

"Desert varnish invariably consists of birnessite in intimate mixture with hematite and large amounts of clay minerals. The clays are generally of the illite-montmorillonite type with minor kaolinite, but in several samples this concentration ratio is reversed."

This sample is a coating on desert pavement rhyolite and quartz cobbles.

Potter, R.M. and G.R. Rossman, 1979, Mineralogy of manganese dendrites and coatings. American Mineralogist, v.64, pp 1219-1226.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: # XRF, EPMA, ICP(Trace), WChem

COMPOSITION
KEYWORD Oxide
ASCII Amount Weight
Percent, % Oxide
html

COMPOSITION: SiO2 34.35 wt% SiO₂

COMPOSITION: TiO2 0.78 wt% TiO₂

COMPOSITION: Al2O3 20.01 wt% Al₂O₃

COMPOSITION: FeO 10.96 wt% FeO

COMPOSITION: MnO 22.63 wt% MnO

COMPOSITION: MgO 2.43 wt% MgO

COMPOSITION: BaO 1.22 wt% BaO

COMPOSITION: CaO 1.28 wt% CaO

COMPOSITION: Na2O 0.23 wt% Na₂O

COMPOSITION: K2O 1.89 wt% K₂O

COMPOSITION: P2O5 1.10 wt% P₂O₅

COMPOSITION: Total 96.88 wt%

COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S

COMPOSITION: New Total wt%

COMPOSITION KEYWORD	Oxide ASCII	Amount	Weight Percent, %	Oxide html
COMPOSITION:	SiO2	34.35	wt%	SiO₂
COMPOSITION:	TiO2	0.78	wt%	TiO₂
COMPOSITION:	Al2O3	20.01	wt%	Al₂O₃
COMPOSITION:	FeO	10.96	wt%	FeO
COMPOSITION:	MnO	22.63	wt%	MnO
COMPOSITION:	MgO	2.43	wt%	MgO
COMPOSITION:	BaO	1.22	wt%	BaO
COMPOSITION:	CaO	1.28	wt%	CaO
COMPOSITION:	Na2O	0.23	wt%	Na₂O
COMPOSITION:	K2O	1.89	wt%	K₂O
COMPOSITION:	P2O5	1.10	wt%	P₂O₅
COMPOSITION:	Total	96.88	wt%
COMPOSITION:	O=Cl,F,S		wt%	#correction for Cl, F, S
COMPOSITION:	New Total		wt%

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

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