|
|
(For further information on spectroscopy, see:
http://speclab.cr.usgs.gov)
TITLE: Fassaite HS118 Pyroxene DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: HS118
MINERAL_TYPE: Inosilicate
MINERAL: Fassaite (Pyroxene group)
FORMULA: Ca(Mg,Fe+3,Al)(Si,Al)2O6
FORMULA_HTML: Ca(Mg,Fe+3,Al)(Si,Al)2O6
COLLECTION_LOCALITY: Helena, MT
ORIGINAL_DONOR: Hunt and Salisbury Collection
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
IMAGE_OF_SAMPLE:
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Primarily pyroxene; best matches are diopside and augite, but this is not definitive. Some amphibole and some chlorite present. Trace of an unidentifiable residual.
Konnert, Judith and Marta Flohr, 1992, unpublished data, USGS Reston, VA.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
Fassaite commonly contains Fe+3 which results in an absorption feature at 0.85µm and ferrous iron which results in a weak band near 1.05µm.
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.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
mode:
90 vol% clinopyroxene (light green)
5 vol% clinopyroxene (dark green)
5 vol% magnetite
trace Fe-oxide staining
average grain size = 292 µm
Smaller grains about 8 µm in diameter coat larger grains up to 15% of their surfaces. Magnetite occurs as inclusions in pyroxene grains. Two cleavages at nearly 90 degrees, biaxial (+), 2V ~ 60 degrees, inclined extinction, pleochroism most intense in darker green grains and I believe all one pyroxene. All these properties are consistent with clinopyroxene, and the 2V is about right for Fassaite. G. Swayze.
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1c2c3c4c # 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 1637 | 0.2-3.0µm | 200 | g.s.= 292 µm |
| LIB_SPECTRA: | splib05a r 2676 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib06a r 7767 | g.s.= | ||
| LIB_SPECTRA: | splib06a r 7779 | g.s.= |