DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: PYX02
MINERAL_TYPE: Inosilicate
MINERAL: Hypersthene (Pyroxene group)
FORMULA: (Mg,Fe+2)2Si2O6 (En86)
FORMULA_HTML: (Mg,Fe+2)2Si2O6 (En86)
COLLECTION_LOCALITY: Bamble, Norway
ORIGINAL_DONOR: Wards Scientific, and Robert B. Singer
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Intermediate member of the series Enstatite-Orthoferrosilite.
The original sample description and vis-nir spectrum was published by:
Singer, R.B., 1981, Near-Infrared spectral reflectance of mineral mixtures: Systematic combinations of pyroxenes, olivine, and iron oxides: J. Geophys Res., v. 86, p. 7967-7982.
The sample is pure pyroxene except for a small (<2%?) amount of tremolite. The tremoilte shows in the spectra as weak (narrow) bands at 2.3 µm and 1.4 µm. Singer suspected the tremolite, but it is confirmed by higher resolution spectra in this library.
The sample was ground and wet sieved in methanol at the USGS Denver Spectroscopy Laboratory by Roger Clark. Sieve intervals are:
5-10 µm (g)
10-20 µm (a)
20-30 µm (d)
30-45 µm (e)
45-104 µm (f)
104-150 µm (b)
150-250 µm (c)
>250 µm (h)
SEM photos were done by R. Clark on each sieve interval to characterize
the grain sizes.
Letter denotes spectrum designation.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
None
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: XRF # XRF, EM(WDS), ICP(Trace), WChem
| COMPOSITION: | SiO2 | 55.30 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 0.05 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 0.12 | wt% | Al2O3 |
| COMPOSITION: | Fe2O3 | (as FeO) | wt% | Fe2O3 |
| COMPOSITION: | FeO | 9.38 | wt% | FeO |
| COMPOSITION: | MnO | 0.15 | wt% | MnO |
| COMPOSITION: | MgO | 32.80 | wt% | MgO |
| COMPOSITION: | Na2O | 0.00 | wt% | Na2O |
| COMPOSITION: | P2O5 | 0.01 | wt% | P2O5 |
| COMPOSITION: | LOI | 2.00 | wt% | LOI |
| COMPOSITION: | Total | 100.28 | wt% | |
| COMPOSITION: | O=Cl,F,S | wt% | #correction for Cl, F, S | |
| COMPOSITION: | New Total | 100.28 | wt% |
COMPOSITION_TRACE:
COMPOSITION_DISCUSSION:
The compositional analysis is from:
Singer, R.B., 1981, Near-Infrared spectral reflectance of mineral
mixtures: Systematic combinations of pyroxenes, olivine, and iron
oxides: J. Geophys Res., v. 86, p. 7967-7982.
All Fe2O3 is reported in the FeO amount. The analysis was performed by XRA Laboratory, Ontario Canada. FeO was by wet chemistry, all else by XRF.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
The sample appears to be pure pyroxene except for a small (<~ 2%) amount of tremolite.
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1_2_3_4_
LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment
LIB_SPECTRA: splib04a r 2263 0.2-3.0µm 200 g.s.=350 µm
LIB_SPECTRA: splib04a r 2274 0.2-3.0µm 200 g.s.=180 µm
LIB_SPECTRA: splib04a r 2285 0.2-3.0µm 200 g.s.=120 µm
LIB_SPECTRA: splib04a r 2296 0.2-3.0µm 200 g.s.=60 µm
LIB_SPECTRA: splib04a r 2308 0.2-3.0µm 200 g.s.=34 µm
LIB_SPECTRA: splib04a r 2319 0.2-3.0µm 200 g.s.=23 µm
LIB_SPECTRA: splib04a r 2330 0.2-3.0µm 200 g.s.=12 µm
LIB_SPECTRA: splib04a r 2341 0.2-3.0µm 200 g.s.= 7 µm
LIB_SPECTRA: splib05a r ____ 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=