Clark and others 2007 USGS Data Series 231
Spectral Library splib06a Sample Description

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

TITLE: Topaz Wigwam_Area_5_#15 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: Wigwam_Area_5_#15

MINERAL_TYPE: Nesosilicate

MINERAL: Topaz

FORMULA: Al2SiO4(F,OH)2

FORMULA_HTML: Al₂SiO₄(F,OH)₂

COLLECTION_LOCALITY: Wigwam Creek #5, Colorado

ORIGINAL_DONOR: Gene Foord

CURRENT_SAMPLE_LOCATION: Gene Foord Collection, USGS

ULTIMATE_SAMPLE_LOCATION: Gene Foord Collection, USGS

SAMPLE_DESCRIPTION:

Most of the (OH^-) in topaz is generally replaced by F^-, the maximum fluorine content being 20.7%.

Hurlbut, C.S., and C. Klein, 1977, Manual of Mineralogy, 19th Ed. John Wiley and Sons, New York, New York, 353p.

Topaz is commonly found as a vapor phase or hydrothermal crystallization product in three principal geologic associations: rhyolites; pegmatites and greisens; and hydrothermal veins. The mineral also occurs as a liquidus phase in ongonites and some rhyolites.

Foord, E.L., L. Jackson, J. Taggart, J. Crock, and T.V.V. King, 1988, Environment of Crystallization of Topaz as Determined From Crystal Chemistry and Infrared Spectra. Program and Abstracts Annual GSA Meeting, October 31-November 3, 1988, Denver CO, A224,#4128.

IMAGE_OF_SAMPLE:
NO PHOTO

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Not Available

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

H₂O^- = 0.01, H₂O⁺= 0.32

Compositions of the 65 topaz samples are grouped in terms of H₂O⁺, F, and trace element content. H₂O⁺ contents for (in wt. %) for rhyolitic topaz ranged from 0.06 to 0.11, pegmatitic topaz from 0.20 to 0.91, and hydrothermal topaz from 1.69 to 2.67; fluorine content is inversely related to water content. This is a pegmatitic topaz.

Foord, E.L., L. Jackson, J. Taggart, J. Crock, and T.V.V. King, 1988, Environment of Crystallization of Topaz as Determined From Crystal Chemistry and Infrared Spectra. Program and Abstracts Annual GSA Meeting, October 31-November 3, 1988, Denver CO, A224,#4128.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2b3b4_ # 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 4859	0.2-3.0µm	200	g.s.=
LIB_SPECTRA:	splib05a r 6836	0.2-3.0µm	200	g.s.=
LIB_SPECTRA:	splib06a r 22829			g.s.=
LIB_SPECTRA:	splib06a r 22841			g.s.=