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: Clinochlore_Fe GDS157 Chlorite DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS157, GDS157.b

MINERAL_TYPE: Phyllosilicate

MINERAL: Ferroan Clinochlore (Ripidolite) (Chlorite group)

FORMULA: (Fe+2,Mg)5Al(Si3Al)O10(OH)8

FORMULA_HTML: (Fe⁺²,Mg)₅Al(Si₃Al)O₁₀(OH)₈

COLLECTION_LOCALITY: Flagstaff Hill, California

ORIGINAL_DONOR: Jim Post

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

This sample is described in:

Post, J.L. and C.C. Plummer, 1972, The chlorite series of Flagstaff Hill area, California: A preliminary investigation. Clays and Clay Minerals, v.20, pp271-283.

Jim Post, 1993, written communication.

The sample GDS157.b is formerly sample GDS307 and was ground and sieved from sample GDS157. GDS157.b is a sieved sample with sieve interval 75 to 150 microns.

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.5-9.5 keV, smear mount (ripidolt.out); 45 kV - 35 mA, 7.3- 9.5 keV, random mount (ripidlt2.out)
References: Bailey (1988), Huebner's reference patterns
Found: Chlorite, type IIb, one weak but distinct reflection at 9.7 Angstroms (mica?), and one very weak reflection at 7.7 Angstroms.
Sought but not found: quartz

Comments: Many sharp reflections indicate very good crystallinity. Ripidlt2 is one of the best chlorite patterns I have ever seen. The chemical analysis places this chlorite in the composition range once called ripidolite. Note that the unidentified reflection at 7.7 Angstroms is also present in clinochlore GDS158."

J.S. Huebner, J. Pickrell, and J. Randow, 1993, written communication.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: # XRF

COMPOSITION
KEYWORD Oxide
ASCII Amount Weight
Percent, % Oxide
html

COMPOSITION: SiO2 25.2 wt% SiO₂

COMPOSITION: TiO2 0.90 wt% TiO₂

COMPOSITION: Al2O3 19.6 wt% Al₂O₃

COMPOSITION: Cr2O3 0.057 wt% Cr₂O₃

COMPOSITION: Fe2O3 25.3 wt% Fe₂O₃

COMPOSITION: NiO 0.051 wt% NiO

COMPOSITION: MnO 0.11 wt% MnO

COMPOSITION: MgO 16.6 wt% MgO

COMPOSITION: CaO 0.11 wt% CaO

COMPOSITION: Na2O 0.27 wt% Na₂O

COMPOSITION: K2O 0.03 wt% K₂O

COMPOSITION: LOI 10.0 wt% LOI

COMPOSITION: Total 98.228 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	25.2	wt%	SiO₂
COMPOSITION:	TiO2	0.90	wt%	TiO₂
COMPOSITION:	Al2O3	19.6	wt%	Al₂O₃
COMPOSITION:	Cr2O3	0.057	wt%	Cr₂O₃
COMPOSITION:	Fe2O3	25.3	wt%	Fe₂O₃
COMPOSITION:	NiO	0.051	wt%	NiO
COMPOSITION:	MnO	0.11	wt%	MnO
COMPOSITION:	MgO	16.6	wt%	MgO
COMPOSITION:	CaO	0.11	wt%	CaO
COMPOSITION:	Na2O	0.27	wt%	Na₂O
COMPOSITION:	K2O	0.03	wt%	K₂O
COMPOSITION:	LOI	10.0	wt%	LOI
COMPOSITION:	Total	98.228	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:

Low order gray interference color, green pleochroic color, basal cleavage, all consistent with chlorite. No other mica obvious, some brown Fe staining present in some grains. G. Swayze.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1a2a3a4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns