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: Montmorillonite CM27 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: CM27

MINERAL_TYPE: Phyllosilicate

MINERAL: Montmorillonite (Bentonite) (Montmorillonite group)

FORMULA: (Na,Ca)0.33(Al,Mg)2Si4O10(OH)2*nH20

FORMULA_HTML: (Na,Ca)_0.33(Al,Mg)₂Si₄O₁₀(OH)₂•nH₂0

COLLECTION_LOCALITY: Belle Fourche, South Dakota

ORIGINAL_DONOR: Clay Mineral Standard, Wards Natural Science Inc

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

A spectrum for this sample was published by:

Clark, R.N., T.V.V. King, M. Klejwa, G. Swayze, and N. Vergo, 1990, High spectral resolution reflectance spectroscopy of minerals: J. Geophys Res. 12653-12680.

Who noted that it was spectrally pure.

IMAGE_OF_SAMPLE:
NO PHOTO

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Analysis by Norma Vergo indicates the sample is bentonite + quartz + feldspar + bassanite; the less than 2µm cut is pure smectite.

END_XRD_ANALYSIS.

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

COMPOSITION
KEYWORD Oxide
ASCII Amount Weight
Percent, % Oxide
html

COMPOSITION: SiO2 57.6 wt% SiO₂

COMPOSITION: TiO2 0.12 wt% TiO₂

COMPOSITION: Al2O3 20.9 wt% Al₂O₃

COMPOSITION: Fe2O3 3.54 wt% Fe₂O₃

COMPOSITION: FeO 0.09 wt% FeO

COMPOSITION: MnO less than 0.02 wt% MnO

COMPOSITION: MgO 2.66 wt% MgO

COMPOSITION: CaO 1.04 wt% CaO

COMPOSITION: Na2O 1.81 wt% Na₂O

COMPOSITION: K2O 0.35 wt% K₂O

COMPOSITION: P2O5 less than 0.05 wt% P₂O₅

COMPOSITION: H2O+ 5.94 wt% H₂O⁺

COMPOSITION: H2O- 5.46 wt% H₂O^-

COMPOSITION: H2O 11.4 wt% H₂O

COMPOSITION: LOI 11.3 wt% LOI

COMPOSITION: Total 99.39 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	57.6	wt%	SiO₂
COMPOSITION:	TiO2	0.12	wt%	TiO₂
COMPOSITION:	Al2O3	20.9	wt%	Al₂O₃
COMPOSITION:	Fe2O3	3.54	wt%	Fe₂O₃
COMPOSITION:	FeO	0.09	wt%	FeO
COMPOSITION:	MnO	less than 0.02	wt%	MnO
COMPOSITION:	MgO	2.66	wt%	MgO
COMPOSITION:	CaO	1.04	wt%	CaO
COMPOSITION:	Na2O	1.81	wt%	Na₂O
COMPOSITION:	K2O	0.35	wt%	K₂O
COMPOSITION:	P2O5	less than 0.05	wt%	P₂O₅
COMPOSITION:	H2O+	5.94	wt%	H₂O⁺
COMPOSITION:	H2O-	5.46	wt%	H₂O^-
COMPOSITION:	H2O	11.4	wt%	H₂O
COMPOSITION:	LOI	11.3	wt%	LOI
COMPOSITION:	Total	99.39	wt%
COMPOSITION:	O=Cl,F,S		wt%	#correction for Cl, F, S
COMPOSITION:	New Total		wt%

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

XRF Analysis by Branch of Analytical Chemistry, USGS, Denver. Total above includes LOI value rather than H₂O values, and does not include value for FeO as it was determined at same time as H₂O. Trace analysis was performed and will be added later.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Trace amounts of limonite, no visible feldspar or quartz, slight HCl fizz.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2b3b4_ # CM27 # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns