|
|
(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Rhodochrosite HS338 DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: HS338
MINERAL_TYPE: Carbonate
MINERAL: Rhodochrosite
FORMULA: MnCO3
FORMULA_HTML: MnCO3
COLLECTION_LOCALITY: Montana
ORIGINAL_DONOR: Hunt and Salisbury Collection
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Rhodochrosite, MnCO3, is a comparatively rare carbonate mineral, usually occurring in hydrothermal veins with ores of silver, lead and copper, and with other manganese minerals. Divalent iron and calcium substitute for manganese, and a complete solid solution series appears to extend to siderite and calcite.
Hunt, G.R., J.W. Salisbury, 1971, Visible and near-infrared spectra of minerals and rocks: II. Carbonates. Modern Geology, v. 2, p. 23-30.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
40 kV - 30 mA, 7.3-9.5 keV
File: rhdch338.out, -.mdi
References: Huebner's reference patterns
Found: Rhombohedral carbonate, minor quartz, unidentified
reflections at 2.88 angstroms
(moderately strong), 2.61i angstroms (moderately weak), and 1.406 angstroms (weak)
Sought but not found: pyrolusite, manganite, Mn-silicates
Comment: Sharp, strong pattern of orthopyroxene. Talc based on four basal compositional homogeneity. The carbonate lattice spacing's are consistent with MnCO3-rich composition, probably in solid solution with hS136.3B Sphalerite magnesite and/or siderite.
J.S.Huebner, J. Pickrell, T. Schaefer, written communication(USGS 1994)
Comment: Sharp, well-formed peaks suggest good degree of crystallization and compositional homogeneity. The carbonate lattice spacing's are consistent with MnCO3-rich composition, probably in solid solution with magnesite and/or siderite.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_TRACE:
COMPOSITION_DISCUSSION:
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1b2_3_4_ # 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 4176 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib05a r 5890 | 0.2-3.0µm | 200 | g.s.= |
| AccessibilityFOIAPrivacyPolicies and Notices | |
 |
|