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.
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