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USGS Spectral Library Version 7 Sample Description

Kokaly, R.F., Clark, R.N., Swayze, G.A., Livo, K.E., Hoefen, T.M., Pearson, N.C., Wise, R.A., Benzel, W.M., Lowers, H.A., Driscoll, R.L., and Klein, A.J., 2017, USGS Spectral Library Version 7: U.S. Geological Survey Data Series 1035, 61 p., https://doi.org/10.3133/ds1035
For more information on the library, see: local link web link

TITLE: Pyrite GDS483 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS483.c

MINERAL_TYPE: Sulfide

MINERAL: Pyrite (Pyrite group)

FORMULA: FeS2

FORMULA_HTML: FeS2

COLLECTION_LOCALITY: Armejun, Spain

COLLECTION_LATITUDE: Not Available # degrees and decimal minutes (N or S)

COLLECTION_LONGITUDE: Not Available # degrees and decimal minutes (W or E)

DATUM: Not Available # coordinate datum

ORIGINAL_DONOR: Roger N. Clark

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms series with Cattierite (CoS2). Dimorphous with Marcasite.

"SS-19. Pyrite. Rico, Colorado (35). Pyrite, FeS2, is the most common and widespread of sulphides. It occurs in igneous, metamorphic and sedimentary rocks, as well as in veins. In the visible, pyrite displays the reflectivity vs. particle size behavior that is peculiar to opaque minerals - ie. reflectivity decreases as particle size decreases. It is also interesting that decreased absorption in the red region of the visible results in a significant contrast in reflectivity from the red to the blue, despite the sample's overall low reflectivity. In the near-infrared, the spectral behavior of pyrite changes from that of an opaque material to that of a transparent one.

This sample was ground from one of the original cubes of pyrite.

Grain size fractions are indicated by the extension after the sample number:
.a = <20µm
.b = 20-30µm
.c = 30-60µm
.d = 60-104µm
.e = 104-150µm
.f = 150-250µm
.g = 250-1000µm
.h = >1000µm

IMAGE_OF_SAMPLE: Not Available

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Major pyrite with minor szomolnokite and minor rhomboclase. (Steve Sutley)

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

No additional compositional details available.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

The major pyrite bands at 24.9µm, 28.8µm and 34.3µm are clearly seen in the far infrared portion of the spectrum. Water from the salts can be seen throughout the spectrum.

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1c2c3d4b # GDS483.c # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns