DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: GDS158
MINERAL_TYPE: Phyllosilicate
MINERAL: Clinochlore (Sheridanite) (Chlorite group)
FORMULA: (Mg,Fe+2)5Al(Si3Al)O10(OH)8
FORMULA_HTML: (Mg,Fe+2)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 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:
45 kV - 35 mA, 6.5-9.5 keV, smear mount (sherd8.out); 40 kV -
30 mA, random mount (sherd8-2.out)
References: Bailey (1988, MSA Reviews 19; 1988 in Clays and Clay
Minerals); Huebner's reference patterns
Found: Chlorite type IIbb. A broad, very weak reflection at
9.6 is probably due to a trace of mica. A weak reflection
at 3.23 angstroms may be due to a trace of feldspar. A weak
unidentified reflection at 2.357 angstroms. And a weak,
unidentified reflection at 7.8 angstroms that also appeared
in GDS157 (the "ripidolite").
Sought but not found: quartz
Comments: With chemical analysis, the chlorite is a clinochlore IIbb.
Severe preferred orientation in smear mounts; fortunately,
there was enough sample for a random mount. Sharp chlorite
reflections indicate excellent crystallinity. With GDS157
("ripidolite"), the best chlorite patterns I have ever
seen."
J.S. Huebner, J. Pickrell, and T.Schaefer, 1994, written communication.
40 kV- 30 mA, 7.3-9.5 keV
File sherd158.out, -.mdi (edge/random mount)
References: Bailey (1988 in Clays and Clay Minerals, 36, 193-213); Huebner's reference
patterns
Found: clinichlore type IIbb, trace rutile
Comment: Sharp reflections suggest excellent crystallinity and compositional
homogeneity. Position of the (060) reflection indicates Mg/(Mg+Fe+Mn) = 0.85.
Presence of rutile confirmed optically; rutile forms thin but very elongate needles in
the chlorite flkes ("rutilated clinochlore").
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: XRF # XRF, EM(WDS), ICP(Trace), WChem
| COMPOSITION: | SiO2 | 27.5 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 1.04 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 19.8 | wt% | Al2O3 |
| COMPOSITION: | Cr2O3 | 0.057 | wt% | Cr2O3 |
| COMPOSITION: | Fe2O3 | 14.1 | wt% | Fe2O3 |
| COMPOSITION: | NiO | 0.074 | wt% | NiO |
| COMPOSITION: | MnO | 0.13 | wt% | MnO |
| COMPOSITION: | MgO | 24.7 | wt% | MgO |
| COMPOSITION: | CaO | 0.10 | wt% | CaO |
| COMPOSITION: | Na2O | 0.22 | wt% | Na2O |
| COMPOSITION: | K2O | 0.03 | wt% | K2O |
| COMPOSITION: | P2O5 | 0.11 | wt% | P2O5 |
| COMPOSITION: | LOI | 11.5 | wt% | LOI |
| COMPOSITION: | Total | 99.361 | wt% | |
| COMPOSITION: | O=Cl,F,S | wt% | #correction for Cl, F, S | |
| COMPOSITION: | New Total | wt% |
J.S.Huebner, J. Pickrell, T. Schaefer, unpublished, written communication (1994)
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
None
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
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 1088 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r ____ 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=