DOCUMENTATION_FORMAT: ELEMENT

SAMPLE_ID: GDS68

MINERAL_TYPE: Element

MINERAL: Carbon

FORMULA: C

FORMULA_HTML: C

COLLECTION_LOCALITY: Synthetic

ORIGINAL_DONOR: Sargent Welch

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

The sample and the visible-NIR spectrum was originally published in:

Clark, R.N., 1983, Spectral Properties of Mixtures of Montmorillonite and Dark Carbon Grains: Implications for Remote Sensing Minerals Containing Chemically and Physically Adsorbed Water: J. Geophys. Res., v. 88, p. 10635-10644.

The sample was manufactured by Sargent Welch (in about 1980) and consists of 99.0 wt% pure carbon, 0.5 wt% ash, and 0.5 wt% acetone extractables. The sample was examined with scanning electron microscopy (SEM) and the grain size is quite uniform at 0.17 µm. Note that the Clark 1983 spectrum has too high a reflectance due to scattered light in the UH spectrometer.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

None

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: Other # XRF, EM(WDS), ICP(Trace), WChem

COMPOSITION:	C:	99.0	wt%	C
COMPOSITION:	volatile:	0.5	wt%	volatile
COMPOSITION:	unknown:	0.5	wt%	unknown
COMPOSITION:	Total	100.0	wt%

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

The sample analysis was by Sargent Welch and consists of 99.0 wt% pure carbon, 0.5 wt% ash, and 0.5 wt% acetone extractables.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

SEM shows the grains to be spherical with a 0.17 µm diameter. No visible contamination under x-polarized light. Clumps range in size greater than 0.17µm.

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 820 0.2-3.0µm 200 g.s.=0.17 µm

LIB_SPECTRA: splib05a r ____ 0.2-3.0µm 200 g.s.=

LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=