Staurolite

Spectrum Details

Modality

NIR

Category

mineral

Material Type

Nesosilicate

Sample ID

HS188.1B, HS188.2B, HS188.3B, HS188.4B

Collection Locality

Fannin County, Georgia

Spectral Purity

1b2_3_4_ # HS188.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns SPECTRAL_PURITY: 1b2_3_4_ # HS188.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns SPECTRAL_PURITY: 1c2c3d4_ # HS188.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns SPECTRAL_PURITY: 1c2_3_4_ # HS188.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns

Composition / XRD

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

Sample Description

N-14 Staurolite 188B--Fannin Co., Georgia. (Fe^2+, Mg)2(Al, Fe^3+)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. 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. Grain size fractions are indicated by the extension after the sample number: .1B = IMAGE_OF_SAMPLE:

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)

X Units

cm⁻¹

Y Units

Absorbance

Data Points

2,126