TITLE: Cordierite HS346 DESCRIPT
COLLECTION_LOCALITY: Guffy, Colorado
ORIGINAL_DONOR: Hunt and Salisbury Collection
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
Forms series with Sekaninaite. Dimorphous with Indialite.
"C-2 Cordierite 346B--Guffy, Colo. 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.
Cordierite + quartz + muscovite + talc (Norma Vergo)
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
52-62 vol% cordierite
30-40 vol% mica (clear)
8 vol% opaques as inclusions in cordierite
Because of significant mica contamination, I suggest this sample be deleted from database. G. Swayze.
LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment
LIB_SPECTRA: splib04a r 1260 0.2-3.0µm 200
LIB_SPECTRA: splib05a r ____ 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=