DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: HS262
MINERAL_TYPE: Sulfide
MINERAL: Arsenopyrite (Arsenopyrite group)
FORMULA: FeAsS
FORMULA_HTML: FeAsS
COLLECTION_LOCALITY: Gold Hill, Utah
ORIGINAL_DONOR: Hunt and Salisbury Collection
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
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. Sulphides and sulphates. Modern Geology, v. 3, p. 1-14.
With the note: "This sample is contaminated with some quartz and a small amount of pyrite and elemental sulphur. Arsenopyrite is opaque and spectrally featureless. Its opacity is caused by the conduction band extending over the entire range, mainly due to the presence of arsenic. The contaminants in this sample are not abundant enough to alter this behaviour, and the fact that the largest paritcle size falls approximately in the middle of its reflectivity range has no real significance."
Sample measured for the library was the 74-250µm sieve interval.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
40 kV - 30 mA, 7.0-9.5 keV
File: arsn263.mdi, *.out (smear mount on quartz plate)
References: JCPDS #42-1320; Huebner's reference patterns
Found: Quartz, arsenopyrite, unindexed weak to very weak reflections at 6.3, 4.5,
3.42, 3.18, 2.86, and 2.75 angstroms
Comment: Quartz reflections of moderate intensity (the (100) peak of nominal
relative intensity 22% did not exceed 200 counts.sec-1), arsenopyrite reflections
much weaker. Unindexed reflections could not be identified, suggesting they may
represent more than one phase. Peaks are symmetric and of normal width, but
alpha1-alpha2 wavelength resolution is poor. Phases are only moderately
crystalline.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_DISCUSSION:
None.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
av gr sz = 265µm for arsenopyrite
59 vol% quartz
40 vol% arsenopyrite
1 vol% elemental sulfur
Optically opaque, grayish yellow metallic luster. Suggest magnetic separation be done on this sample. G. Swayze.
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1_2_3_4_
LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment
LIB_SPECTRA: splib04a r 583 0.2-3.0µm 200 g.s.= 265µm
LIB_SPECTRA: splib05a r ____ 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=