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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Lepidolite NMNH105538 DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: NMNH105538
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: Stewart Mine, San Diego County, California
ORIGINAL_DONOR: National Museum of Natural History
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Pink, lilac and gray mica.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
40 kV - 30 mA, 6.5-9.5 keV
File: lp105538.mdi (random mt)
References: JSH's reference patterns; JCPDS patterns for micas; Deer, Howie, & Zussman
(1962); Bailey (1984a,b); PDF2 #24-062, 24-0594, 06-0263, 43-0685, 42-1399, 42-0604,
15-0062
Found: Two polytypes of lepidolite-group micas
Comment: Peaks are narrow and symmetric; some peak tips are split as if two similar
phases (or compositions of one phase) are present. The alpha1-alpha2 components are not
resolved. Huebner's reference patterns and JCPDS patterns for lepidolite, muscovite 2M1
and 2M2, and Zinnwaldite 1M are similar to that obtained from the sample. No single
mineral pattern successfully accounts for all of the peaks observed in the pattern.
Search matches based upon the eight strong reflections and upon the full profile did not
account for the intensity of the reflection at 4.96 angstroms or yield otherwise
convincing results. Best agreement was obtained with PDF2 #15-0062, lepidolite 12O,
which has a strong (00.24) superlattice reflection at 4.96 angstroms. but which,
surprisingly, was not identified by the search-match routines. Minor reflections are
adequately explained the addition of 43-0692, lepidolite 2M2. The original sample is
formed of compact masses of lavendar crystals characteristic of lepidolite.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_TRACE:
None
COMPOSITION_DISCUSSION:
None
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1a2_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 2747 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib05a r 4123 | 0.2-3.0µm | 200 | g.s.= |
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