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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Axinite HS342 DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: HS342
MINERAL_TYPE: Cyclosilicate
MINERAL: Axinite (Axinite group)
FORMULA: (Ca,Mn,Fe+2)3Al2BO3Si4O15(OH)
FORMULA_HTML: (Ca,Mn,Fe+2)3Al2BO3Si4O15(OH)
COLLECTION_LOCALITY: Mexico
ORIGINAL_DONOR: Hunt and Salisbury Collection
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
"(Ca, Fe2+, Mn)3Al2(BO3)(Si4O12)(OH): Axinite is found in contact-altered calcareous rocks and in hydrothermal veins. Its spectrum reveals iron bands in the visible and an extremely intense feature centered near 1.2µm, together with a broad feature to longer wavelengths."
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, vol. 4, pp 85-106.
74-250µm sieve interval.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
40 kV - 30 mA, 6.5-9.5 keV
File: axint342_mdi, *.out (smear mount on quartz plate)
References: JCPDS #29-344, 27-76, 6-444, 27-84; Huebner's reference patterns
Found: mineral of axinite group; very weak reflections at 2.86, 2.12, 1.95, and
1.755 angstroms
Sought but not found: actinilite, andradite, biotite, calcite, datolite, epidote,
feldspars, fluorite, hedenbergite, laumonite, prehnite, pyrite, quartz, tourmaline,
zoisite
Comment: Very sharp reflections indicate excellent crystallinity. Members of the
axinite group have similar unit cell dimensions. Based on peak positions, we
suggest that HS-342 is ferroaxinite, tinzenite, or manganaxinite, but not
magnesioaxinite.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
No compositional analyses available
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
Optical examination gives the following mineral mode:
99 vol% axinite
1 vol% wh. mica?
avg. grain size = 330µm
Flaky fractured axinite grains with faint pink color. One distinct cleavage, high relief, inclined extinction, and (-) biaxial with 2V=40/(de. All these optical properties are consistent with axinite. G. Swayze
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 625 | 0.2-3.0µm | 200 | g.s.= 330 µm |
| LIB_SPECTRA: | splib05a r 1274 | 0.2-3.0µm | 200 | g.s.= |
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