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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Lepidolite HS167 DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: HS167
MINERAL_TYPE: Phyllosilicate
MINERAL: Lepidolite (Mica group)
FORMULA: K(Li,Al)3(Si,Al)4O10(F,OH)2
FORMULA_HTML: K(Li,Al)3(Si,Al)4O10(F,OH)2
COLLECTION_LOCALITY: Keystone, S. Dakota
ORIGINAL_DONOR: Hunt and Salisbury Collection
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Original Spectrum published in: Hunt, G.R., J.W. Salisbury, and C.J. Lenhoff, 1973, Visible and near-infrared spectra of minerals and rocks: VI. Additional silicates. Modern Geology, v. 4, p. 85-106.
With the note:"In addition to the substitutions given in the general formula for lepidolite, considerable amounts of sodium, rubidium and cesium may substitute for potassium; and iron, manganese and magnesium may substitute for aluminum. It is the substituted ferric iron and manganese that give rise to the bands at 0.8µ, 0.55 µ, and 0.45µ, together with the drop off to the extreme blue. The band near 1.4µ is due to the overtone of the OH stretching fundamental, and the very weak band at 1.9µ indicates that a small amount of included water is present. The bands near 2.2µ, 2.35µ, and 2.45µ are also due to combination bands involving the OH stretch and possibly the Al-O-H bending mode (at 2.2µ) as discussed above, and the very weak bands at 1.28µ, 1.33µ, 2.03µ and 2.14µ are OH combined with lattice modes."
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
40 kV - 30 mA, 6.5-9.5 keV
File: lpd1673B.mdi (thick smear on quartz plate)
References: Huebner's reference patterns; JCPDS patterns for micas; Deer, Howie,
and Zussman (1962); Bailey (1984a,b); PDF2 #33-1161, 42-1399, 41-1480,
15-0062, 09-0466
Found: Quartz, a lepidolite-group mica, minor albite
Comment: The pattern is dominated by strong, sharp quartz reflections. Mica
reflections are sharp but not sufficiently intense to show clear separation of
alpha1-alpha2 components, even at high 2 theta. The mica phase was compared to
Huebner's reference patterns and the JCPDS mica indexes. Both 2M1 and 2M2
lepidolites and muscovites yield good matches. Search-match based on eight strong
lines returns quartz, zinnwaldite, and calcian albite; little of the intensity of a
reflection at 4.96 angstroms was explained by zinnwaldite (002). Profile based
search-match returned quartz, ordered albite, zinnwaldite, lepidolite-12O as
likely hits. The reflection at 4.96 angstroms is explained by lepidolite
superlattice reflection (00.12); zinnwaldite contributes little to the
interpretation of the pattern. Examination of the original sample shows a
distinctive lavendar-violet color implying that a member of the lepidolite mica
group is present.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_TRACE:
COMPOSITION_DISCUSSION:
None.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1b2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
| LIB_SPECTRA_HED: | where | Wave Range | Av_Rs_Pwr | Comment |
|---|---|---|---|---|
| LIB_SPECTRA: | splib04a r 2737 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib05a r 4111 | 0.2-3.0µm | 200 | g.s.= |
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