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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
For more information on the library, see: local link web link

TITLE: Chlorite + Epidote + Calcite GDS312 - GDS314, GDS319 DESCRIPT

DOCUMENTATION_FORMAT: MIXTURE

SAMPLE_ID: GDS312, GDS313, GDS314, GDS319

MIXTURE_TYPE: Intimate

MIXTURE: Chlorite + Epidote + Calcite

FORMULA: (Mg,Fe)3(Si,Al)4O10(OH)2-(Mg,Fe)3(OH)6 + Ca2(Al,Fe+3)3(SiO4)3(OH) + CaCO3

FORMULA_HTML: (MgFe)3(SiAl)4O10(OH)2-(MgFe)3(OH)6 +Ca2(Al,Fe+3)3(SiO4)3(OH) + CaCO3

COLLECTION_LOCALITY: Calcite from Mexico and Epidote from Prince Wales Island, and Chlorite from Flagstaff Hill, California.

ORIGINAL_DONOR: Purchased from Egger's Lapidary

COLLECTION_LATITUDE: Not Available # degrees and decimal minutes (N or S)

COLLECTION_LONGITUDE: Not Available # degrees and decimal minutes (W or E)

DATUM: Not Available # coordinate datum

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Samples constructed from ground and sieved pure minerals GDS157 (chlorite), GDS297 (epidote), and GDS298 (calcite) in variable proportions.
20wt% Chlorite + 60wt% Epidote + 20 wt% Calcite GDS312
60wt% Chlorite + 20wt% Epidote + 20 wt% Calcite GDS313
20wt% Chlorite + 20wt% Epidote + 60 wt% Calcite GDS314
33wt% Chlorite + 33wt% Epidote + 33 wt% Calcite GDS319

For further information pertaining to this sample see: Dalton, B.J., Bove, D., Mladnich, C., Clark, R.N., Rockwell, B., Swayze, G.A., King, T., Church, S., Spectral Classification Of Similar Materials Using the Tetracorder Algorithm: the Calcite-Epidote-Chlorite Problem, Proceedings of the Tenth JPL Airborne Earth Science Workshop, Jet Propulsion Laboratory Publication 02-1, pp.93-101.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Samples were identified as pure.

For further information pertaining to this sample see: Dalton, B.J., Bove, D., Mladnich, C., Clark, R.N., Rockwell, B., Swayze, G.A., King, T., Church, S., Spectral Classification Of Similar Materials Using the Tetracorder Algorithm: the Calcite-Epidote-Chlorite Problem, Proceedings of the Tenth JPL Airborne Earth Science Workshop, Jet Propulsion Laboratory Publication 02-1, pp.93-101.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: NONE # XRF, EPMA, ICP(Trace),WChem

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

None

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

None

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

Spectra have absorptions characteristic of chlorite, epidote, and calcite. Because these are intimate mixtures the dark components dominate spectrally. In the 0.35 - 2 micron region the strong Fe absorptions of chlorite dominate the spectra. In the 2 - 2.5 micron region chlorite and epidote absorptions dominate with little evidence of the calcite 2.34 micron absorption.

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1a2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns