U.S. Geological Survey home page


Clark et. al. 2003 USGS Open File Report 03-395
Spectral Library splib05a Sample Description

(For further information on spectrsocopy, see: http://speclab.cr.usgs.gov)

TITLE: Staurolite HS188 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS188

MINERAL_TYPE: Nesosilicate

MINERAL: Staurolite

FORMULA: Fe(+2)2Al9O6(SiO4)4(O,OH)2

FORMULA_HTML: Fe2+2Al9O6(SiO4)4(O,OH)2

COLLECTION_LOCALITY: Fannin County, Georgia

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

N-14 Staurolite 188B--Fannin Co., Georgia. (Fe2+, Mg)2(Al, Fe3+)9O6 (SiO4)4(O, OH)2: Staurolite, like kyanite and sillimanite is a typical mineral found in medium grade metamorphosed argillaceous rocks. It is produced at a lower temperature-pressure than is kyanite. This spectrum shows strong general absorption to both long and short wavelengths which produces an apparent reflectivity maximum near 1.05 µ. The fall off to longer wavelengths must be due to generalized hydroxyl and water absorptions and is quite similar in appearance to the spectrum of diaspore (see Part III, p. 200, spectrum (-6). The fall off in the visible must be due to absorptions by ferrous and ferric iron.

Sieve interval 74 - 250µm.

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:

40 kV - 30 mA, 7.3-9.5 keV
File: staur188.out, -.mdi
References: JCPDS # 41-1484; Huebner's reference patterns
Found: quartz, staurolite, K-mica

Comment: All components appear well crystallized and in significant representation with quartz, staurolite, mica. All reflections are accounted for. The mica basal reflection at 10 angstroms appears to be a doublet but next 4.95 does not. >

J.S.Huebner, J. Pickrell, T. Schaefer, written communication(1994 USGS)

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns

LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment
LIB_SPECTRA: splib04a r 4615 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 6402 0.2-3.0µm 200 g.s.=


USA.gov logo  Take Pride in America button