TITLE: Arsenopyrite HS262 DESCRIPT
MINERAL: Arsenopyrite (Arsenopyrite group)
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
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.
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.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
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.
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.=