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: Palygorskite CM46a Attapulgite DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: CM46a

MINERAL_TYPE: Phyllosilicate

MINERAL: Palygorskite (Attapulgite)

FORMULA: (Mg,Al)2Si4O10(OH)*4H2O

FORMULA_HTML: (Mg,Al)₂Si₄O₁₀(OH)•4H₂O

COLLECTION_LOCALITY: Quincy, Florida

ORIGINAL_DONOR: Clay Mineral Standard from Wards Natural Science Inc.

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Spectrum published in: 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. 95, 12653-12680.

Who note the sample is spectrally pure, no smectite bands.

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Analysis by Norma Vergo indicates Palygorskite, medium amount of quartz, trace amount of smectite.

END_XRD_ANALYSIS.

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

COMPOSITION
KEYWORD Oxide
ASCII Amount Weight
Percent, % Oxide
html

COMPOSITION: SiO2 56.0 wt% SiO₂

COMPOSITION: TiO2 0.48 wt% TiO₂

COMPOSITION: Al2O3 10.6 wt% Al₂O₃

COMPOSITION: Fe2O3 3.76 wt% Fe₂O₃

COMPOSITION: MnO less than 0.02 wt% MnO

COMPOSITION: MgO 8.56 wt% MgO

COMPOSITION: CaO 1.35 wt% CaO

COMPOSITION: Na2O less than 0.15 wt% Na₂O

COMPOSITION: K2O 0.95 wt% K₂O

COMPOSITION: P2O5 0.59 wt% P₂O₅

COMPOSITION: LOI 17.0 wt% LOI

COMPOSITION: Total 99.46 wt%

COMPOSITION KEYWORD	Oxide ASCII	Amount	Weight Percent, %	Oxide html
COMPOSITION:	SiO2	56.0	wt%	SiO₂
COMPOSITION:	TiO2	0.48	wt%	TiO₂
COMPOSITION:	Al2O3	10.6	wt%	Al₂O₃
COMPOSITION:	Fe2O3	3.76	wt%	Fe₂O₃
COMPOSITION:	MnO	less than 0.02	wt%	MnO
COMPOSITION:	MgO	8.56	wt%	MgO
COMPOSITION:	CaO	1.35	wt%	CaO
COMPOSITION:	Na2O	less than 0.15	wt%	Na₂O
COMPOSITION:	K2O	0.95	wt%	K₂O
COMPOSITION:	P2O5	0.59	wt%	P₂O₅
COMPOSITION:	LOI	17.0	wt%	LOI
COMPOSITION:	Total	99.46	wt%

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

Analysis by E. Brandt, and J. H. Christie at USGS Branch of Geophysics, Denver

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

90-95 vol% palygorskite
5-10 vol% quartz
trace opaque grains

Bimodal grain size distribution:

population 1 430µm 70 vol%
population 2 30µm 30 vol%

avg. grain size = 176µm

Light grayish white color, quartz grains do not have palygorskite coatings. Trace opaques sparsely spot palygorskite grains. G. Swayze.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2_3_4_ # CM46a # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns