Rhodochrosite

Spectrum Details

Modality

FTIR

Category

mineral

Material Type

Carbonate

Sample ID

HS338.3B, HS338.6

Collection Locality

Montana

Spectral Purity

1b2b3b4_ # HS338.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns SPECTRAL_PURITY: 1b2_3_4_ # HS338.6 # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns

Composition / XRD

None # XRF, EPMA, ICP(Trace), WChem COMPOSITION_TRACE:

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. Grain size fractions are indicated by the extension after the sample number: .3B = 74-250 µm .6 = cut slab IMAGE_OF_SAMPLE:

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: The carbonate lattice spacing's are consistent with MnCO3-rich composition. 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. J.S.Huebner, J. Pickrell, T. Schaefer, written communication(USGS 1994)

X Units

cm⁻¹

Y Units

Absorbance

Data Points

1,801