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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: Sphene, Titanite HS189 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS189

MINERAL_TYPE: Nesosilicate

MINERAL: Titanite (Sphene)

FORMULA: CaTiSiO5

FORMULA_HTML: CaTiO(SiO4)

COLLECTION_LOCALITY: Ontario, Canada

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

"N-16 Sphene 189B--Ontario. CaTiO(SiO4): Sphene is a widespread accessory mineral in igneous and metamorphic rocks. Calcium may be replaced partially by strontium and barium, or by the rare earths and thorium, the higher valencies of the latter being balanced by the entry of trivalent iron and aluminum into the titanium position. The titanium may be partially replaced by Sn, Nb and Ta, with possible compensation of Na replacing Ca. Finally, one O may be replaced by OH or F. This particular sample is a dark reddish brown, apparently due primarily to both the ferric iron and titanium, as described for rutile (see Part III, p. 204, spectrum 0-15A). The presence of about 5 percent opaque magnetite lowers the overall reflectivity of this sample."

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, 6.5-9.5 keV
File: sphen189.out, -.mdi
References: Borg and Smith (1969); JCPDS #25-117; WAR-0612; Huebner's reference pattern
Found: Titanite, minor quartz, albite, unidentified weak reflections at 7.1, 3.03, 2.90, and 2.71 angstroms

Comment: Titanoite is the preferred name for sphene. The albite is very sodic, but the pattern is not sufficiently strong for determination of the structural state by the method of Wright (1968)

J.S.Huebner, J.Pickrell, T. Schaefer,written communication (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 4593 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 6378 0.2-3.0µm 200 g.s.=


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