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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: Chalcopyrite HS431 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS431

MINERAL_TYPE: Sulfide

MINERAL: Chalcopyrite (Chalcopyrite group)

FORMULA: CuFeS2

FORMULA_HTML: CuFeS2

COLLECTION_LOCALITY: Quebec

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms series with Eskebornite.

Spectra for this sample were originally published in: Hunt, G.R., J.W. Salisbury, and C.J. Lenhoff, 1971, Visible and near-infrared spectra of minerals and rocks: IV. Sulfides and sulfates Modern Geology, v. 3, p. 1-14.

With the note: "It exhibits typical opaque behavior, decreasing in reflectivity as its particle size is reduced. It is not, however, spectrally featureless. A fall-off in the reflectivity toward the blue, together with a weak band near 0.9µm, results in the characteristic brass-yellow color of this mineral. Both spectral features are due to iron, which is present in chalcopyrite in the trivalent state (Deer et al., 1962). The copper also makes a contribution to the feature near 0.9µm. This sample is contaminated with approximately 10% pyrrhotite, which has no appreciable effect on the spectrum."

Sample measured for the library was the 74-250µm sieve interval.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 7.3-9.5 keV
File: chpyr431_mdi, *.out (smear mount on quartz plate)
References: JCPDS #37-471, #5-566; Huebner's reference patterns
Found: Chalcopyrite, minor sphalerite

Comment: Moderately sharp, symmetrical peaks suggest moderate crystallinity and compositional heterogeneity. Sphalerite lattice spacing's consistent with ZnS composition (Fe-poor sphalerite).

J.S. Huebner, J. Pickrell, and T. Schaefer, 1994, written communication.

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

None.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Mode:
95 vol% chalcopyrite (yellow-gold color)
5 vol% pyrrhotite (slightly magnetic)
trace quartz

Opaque, yellow-gold metallic luster, uneven fracture. G. Swayze.

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 905 0.2-3.0µm 200 g.s.= 246 µm
LIB_SPECTRA: splib05a r 1614 0.2-3.0µm 200 g.s.=


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