Clark and others 2007 USGS Data Series 231
Spectral Library splib06a Sample Description

(For further information on spectroscopy, see: http://speclab.cr.usgs.gov)

TITLE: Lepidolite NMNH105541 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: NMNH105541

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: Unknown

ORIGINAL_DONOR: National Museum of Natural History

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

None

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.5-9.5 keV
File: lp105538.mdi (smear mount on quartz plate)
References: JSH's Reference Patterns; PDF2 #07-0042, 12-0236, 15-0062, 21-0952, 29-0822, 31-1045, 35-0423, 42-1399.
Found: Mica (species related to lepidolite)

Comment: Peaks are sharp and symmetric. The alpha1-alpha2 components are poorly resolved, only at high 2 theta. Intense basal reflections dominate the pattern. The (002) and (003) peaks are stronger than the (001). Computer search-match routines give suspect results. Manual overlay of numerous mica patterns led to rejection of lepidolite-12O, 1M-polylithionite, 1M taeniolite, and 2M1 ephesite. Best matches in terms of numbers (small) and positions of peaks observed are given by 1M zinnwaldite, 1M taeniolite, 1M matsutomilite, and 3T muscovite. No single pattern accounted for all observed peaks, but all observed peaks are found in this set of four mica patterns. Sample forms compact lavender plates, suggestive of the lepidolite group.

END_XRD_ANALYSIS.

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

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

Spectral comparison with lepidolite NMNH105538 indicates a very close spectral match suggesting this sample is lepidolite.

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 2777	0.2-3.0µm	200	g.s.=
LIB_SPECTRA:	splib05a r 4135	0.2-3.0µm	200	g.s.=
LIB_SPECTRA:	splib06a r 12766			g.s.=