DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: GDS70.a, GDS70.b, GDS70.c, GDS70.d, GDS70.e
MINERAL_TYPE: Nesosilicate
MINERAL: Olivine (Olivine group)
FORMULA: Mg2SiO4-Fe2SiO4 Fo89
FORMULA_HTML: Mg2Si4-Fe2SiO4 Fo89
COLLECTION_LOCALITY: South Point, Hawaii, Hawaii
ORIGINAL_DONOR: Roger N. Clark
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
This sample is commonly referred to as the "green sand beach" olivine. The sample was sieved into grain size fractions. All samples were examined using a petrographic microscope and hand-picked prior to wet-sieving.
King, T.V.V. and W.I. Ridley, 1987, Relation of the Spectroscopic Reflectance of Olivine to Mineral Chemistry and Some Remote Sensing Implications. J. Geophys. Res., 11,457-11,469.
Grain size fractions are indicated by the extension after the sample number:
.e = less than 30µm
.d = less than 60µm
.c = 60-104µm with a median grain size of 70µm
.b = 104-150µm with a median grain size of 115µm
.a = 150-250µm with a median grain size of 165µm
IMAGE_OF_SAMPLE:
NO PHOTO
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Forsterite plus possible trace corundum. (Steve Sutley)
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: EPMA # XRF, EPMA, ICP(Trace), WChem
COMPOSITION KEYWORD |
Oxide ASCII |
Amount | Weight Percent, % |
Oxide html |
---|---|---|---|---|
COMPOSITION: | SiO2 | 41.09 | wt% | SiO2 |
COMPOSITION: | TiO2 | 0.01 | wt% | TiO2 |
COMPOSITION: | Cr2O3 | 0.05 | wt% | Cr2O3 |
COMPOSITION: | FeO | 9.16 | wt% | FeO |
COMPOSITION: | NiO | 0.39 | wt% | NiO |
COMPOSITION: | MnO | 0.21 | wt% | MnO |
COMPOSITION: | MgO | 49.29 | wt% | MgO |
COMPOSITION: | CaO | 0.03 | wt% | CaO |
COMPOSITION: | Total | 100.23 | wt% | |
COMPOSITION: | O=Cl,F,S | wt% | #correction for Cl, F, S | |
COMPOSITION: | New Total | wt% |
COMPOSITION_TRACE:
COMPOSITION_DISCUSSION:
Microprobe analysis by W.I. Ridley at the USGS microprobe facility in Denver, Colorado.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
This appears to be a pure mineral separate through the microscope. Some spectra show weak 2.3 µm alteration features. The rest of the spectrum rates an "a" on the spectral purity scale. Because of the trace alteration, however, the spectra rate a "b" overall.
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION: There are notably deep C-H stretch absorptions around 3.4 microns in grain size series members "d" and "e", which lower the overall spectral purity rating in those regions. G. Swayze.
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1b2b3b4b # GDS70.a # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2b3b4b # GDS70.b # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2b3b4b # GDS70.c # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2c3b4b # GDS70.d # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2c3b4b # GDS70.e # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns