ORIGINAL_DONOR: Sargent Welch
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
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 extractable's. 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.
COMPOSITIONAL_ANALYSIS_TYPE: Other # XRF, EPMA, ICP(Trace), WChem
The sample analysis was by Sargent Welch and consists of 99.0 wt% pure carbon, 0.5 wt% ash, and 0.5 wt% acetone extractable's.
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.
SPECTRAL_PURITY: 1a2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns