SAMPLE_ID: GDS157
MINERAL_TYPE: Phyllosilicate
MINERAL: Ferroan Clinochlore (Ripidolite) (Chlorite group)
FORMULA: (Fe+2,Mg)5Al(Si3Al)O10(OH)8
FORMULA_HTML: (Fe+2,Mg)5Al(Si3Al)O10(OH)8
COLLECTION_LOCALITY: Flagstaff Hill, California
ORIGINAL_DONOR: Jim Post
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
This sample is described in:
Post, J.L. and C.C. Plummer, 1972, The chlorite series of Flagstaff Hill area, California: A preliminary investigation. Clays and Clay Minerals, v.20, pp271-283.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
40 kV - 30 mA, 6.5-9.5 keV, smear mount (ripidolt.out); 45 kV -
35 mA, 7.3- 9.5 keV, random mount (ripidlt2.out)
References: Bailey (1988), Huebner's reference patterns
Found: Chlorite, type IIb, one weak but distinct reflection at
9.7 angstroms (mica?), and one very weak reflection at 7.7
angstroms.
Sought but not found: quartz
Comments: Many sharp relections indicate very good crystallinity.
Ripidlt2 is one of the best chlorite patterns I have
ever seen. The chemical analysis places this chlorite
in the composition range once called ripidolite. Note
that the unidentified reflection at 7.7 angstroms is also
present in sheridanite GDS158."
J.S. Huebner, J. Pickrell, and J. Randow, 1993, written communication.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: # XRF
| COMPOSITION: | SiO2 | 25.2 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 0.90 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 19.6 | wt% | Al2O3 |
| COMPOSITION: | Cr2O3 | 0.057 | wt% | Cr2O3 |
| COMPOSITION: | Fe2O3 | 25.3 | wt% | Fe2O3 |
| COMPOSITION: | NiO | 0.051 | wt% | NiO |
| COMPOSITION: | MnO | 0.11 | wt% | MnO |
| COMPOSITION: | MgO | 16.6 | wt% | MgO |
| COMPOSITION: | CaO | 0.11 | wt% | CaO |
| COMPOSITION: | Na2O | 0.27 | wt% | Na2O |
| COMPOSITION: | K2O | 0.03 | wt% | K2O |
| COMPOSITION: | LOI | 10.0 | wt% | LOI |
| COMPOSITION: | Total | 98.228 | wt% | |
| COMPOSITION: | O=Cl,F,S | wt% | #correction for Cl, F, S | |
| COMPOSITION: | New Total | wt% |
Jim Post, 1993, written communication.
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
None
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
Low order gray interference color, green pleochroic color, basal
cleavage, all consistent with chlorite. No other mica obvious, some
brown Fe staining present in some grains. G. Swayze.
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 1076 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=