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: Ammonio-Illite/Smectite GDS87 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS87

MINERAL_TYPE: Phyllosilicate

MINERAL: Ammonium_Illite/Smectite (Synthetic)

FORMULA: NH4Al2(Si3Al)O10(OH)2 + (NH4)0.33(Al,Mg)2Si4O10(OH)2*nH2O

FORMULA_HTML: NH₄Al₂(Si₃Al)O₁₀(OH)₂ + (NH₄)_0.33(Al,Mg)₂Si₄O₁₀(OH)₂•nH₂O

COLLECTION_LOCALITY: Synthetic

ORIGINAL_DONOR: Dennis Krohn, USGS Reston

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.5-9.5 keV
File: amilsm87_mdi (smear on quartz plate)
References: Deer, Howie and Zussman (1962); Srodon and Eberl (1984); PDF2 #29-1496
Found: Rectorite and/or illite
Sought: illite, mascagnite

Comment: The pattern consists of broad peaks, some having shoulders or tails extending toward lower d-spacings. The alpha1-alpha2 reflections are not resolved. Both rectorite (29-1495, a 1:1 regularly interstratified dioctahedral mica and dioctahedral smectite) and 1M illite (29-1496) explain most features of the pattern. Neither has a basal reflection exactly in the observed position, 11.0 Angstroms. Weak but sharp and symmetric reflections at 6.10 and 5.45 Angstroms are not identified; in a subsequent bulk mount, the intensity at 5.45 Angstroms was greatly enhanced and that at 6.10 Angstroms greatly reduced. Glycolation of the bulk mount so reduced all intensities that the pattern was useless.

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2b3b4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns