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USGS Spectral Library Version 7 Sample Description

Kokaly, R.F., Clark, R.N., Swayze, G.A., Livo, K.E., Hoefen, T.M., Pearson, N.C., Wise, R.A., Benzel, W.M., Lowers, H.A., Driscoll, R.L., and Klein, A.J., 2017, USGS Spectral Library Version 7: U.S. Geological Survey Data Series 1035, 61 p., https://doi.org/10.3133/ds1035
For more information on the library, see: local link web link

TITLE: Siderite HS271 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS271.1B, HS271.2B, HS271.3B, HS271.4B

MINERAL_TYPE: Carbonate

MINERAL: Siderite (Calcite group)

FORMULA: FeCO3

FORMULA_HTML: FeCO3

COLLECTION_LOCALITY: Roxbury, Connecticut

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms series with Magnesite and with Rhodochrosite.

"C-7. Siderite. Roxbury, Conn. (68, hand-ground). Siderite, FeCO3, is found in extensive sedimentary beds, frequently contaminated with clay or organic matter. It is also commonly deposited in veins by hydrothermal solutions. Both magnesium and manganese commonly substitute for the iron. This particular sample is coarsely crystalline and medium brown in color. It is high in iron, as indicated by the strong ferrous ion band near 1.1µ. It is also slightly contaminated with magnetite. Being an opaque material, the magnetite lowers the overall reflectivity of the sample, makes the carbonate bands less prominent, and causes the crossover of the spectral curves in the visible. Analysis shows that this sample contains 0.98% Mg2+ and 7.03% Mn+2. However, the electronic transitions of iron dominate the spectrum to such an extent that none of the sharp features due to Mn++ are apparent in the visible spectrum." NOTE: This a different sample number than this sample (271) but the collection locality is the same. Possibly a mislabeled sample.

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:
.1B = <5 µm
.2B = <74 µm
.3B = 74-250 µm
.4B = 250-1200 µm

IMAGE_OF_SAMPLE:
Photo of sample

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Pure siderite
Possibly some manganoan siderite also - patterns too similar to differentiate.

Konnert, Judith and Marta Flohr, 1992, unpublished data, USGS Reston, VA.

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1a2_3_4_ # HS271.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1a2_3_4_ # HS271.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1a2a3a4_ # HS271.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1a2_3_4_ # HS271.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns