Sample Description USGS Spectral Library Version 7

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
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TITLE: Mascagnite GDS65 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS65.a, GDS65.b

MINERAL_TYPE: Sulfate

MINERAL: Mascagnite (Ammonium Sulfate)

FORMULA: (NH4)2SO4

FORMULA_HTML: (NH₄)₂SO₄

COLLECTION_LOCALITY: None, Chemical Reagent

ORIGINAL_DONOR: None

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

The sample is from a chemical reagent, pure.

Grain size fractions are indicated by the extension after the sample number:
.a = coarse fraction (lumps of average grain size 300µm are in polygranular masses with average size of 600µm)
.b = fine fraction (average grain size = 150µm)

IMAGE_OF_SAMPLE:
NO PHOTO

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV-30 mA, 6.5-9.5 keV
File: mascag65.mdi (smear on quartz plate)
References: PDF2 #40-0660, 41-0621
Found: Mascagnite

Comments: Peaks are very sharp and some show excellent resolution of the alpha1-alpha2 components. Search-match returned no satisfactory hits. PDF2 #40-0660 (synthetic (NH4)2SO4) matches the observed pattern; 41-0621, also a synthetic ammonium sulfate, does not match as well. There is a severe discrepancy in that the (200) reflection, at 3.89 Angstroms in mascag65, has relative intensity eight times greater than in either reference pattern. Some peak shoulders, for instance the (200), and split tips, as in the case of the (020) and (111), are not explained by the PDF2 data.

END_XRD_ANALYSIS.

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

COMPOSITION_DISCUSSION:

Chemical Reagent, pure.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Crystals appear pure under the microscope.

The coarse fraction: Clumps of average grain size 300µm are in polygranular masses with average size of 600µm. G. Swayze

The fine fraction: average grain size = 150µm R. Clark

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1a2a3a4_ # GDS65.a # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1a2a3a4_ # GDS65.b # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns