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

TITLE: Cordierite-QtzMus HS346 DESCRIPT

DOCUMENTATION_FORMAT: MIXTURE

SAMPLE_ID: HS346.1B, HS346.2B, HS346.3B, HS346.4B

MIXTURE_TYPE: Intimate

MIXTURE: Cordierite, quartz, muscovite, and talc

FORMULA: Mg2Al4Si5O18 + SiO2 + KAl2(Si3Al)O10(OH,F)2 + Mg3Si4O10(OH)2

FORMULA_HTML: Mg₂Al₄Si₅O₁₈ + SiO₂ + KAl₂(Si₃Al)O₁₀(OH,F)₂ + Mg₃Si₄O₁₀(OH)₂

COLLECTION_LOCALITY: Guffy, Colorado

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms series with Sekaninaite. Dimorphous with Indialite.

"C-2 Cordierite 346B--Guffy, Co . Al₃(Mg, Fe²⁺)₂ (Si₅Al0₁₈): Cordierite is a mineral of metamorphic origin usually found in gneisses and crystalline schists, or in contact metamorphic zones. Its spectrum shows a weak Fe²⁺ feature at 0.95 µ, which is in accord with typical cordierite composition, and weak broad hydroxyl and water features at 1.4, 1.9, and 2.2 µ which are not. These latter bands are due to alteration products, principally muscovite. Reflectivities I through IV are 50%, 43%, 31%, and 12% at 1.0 µ."

Hunt, G.R., J.W. Salisbury, and C.J. Lenhoff, 1973, Visible and near-infrared spectra of minerals and rocks: VI. Additional silicates. Modern Geology, v. 4, p. 85-106.

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Cordierite + quartz + muscovite + talc (Norma Vergo)

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

mode:
52-62 vol% cordierite
30-40 vol% mica (clear)
8 vol% opaques as inclusions in cordierite

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1c2_3_4_ # HS346.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS346.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2c3c4c # HS346.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS346.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns