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DOCUMENTATION_FORMAT: Man_Made
SAMPLE_ID: GDS803
MATERIAL_TYPE: Paint Pigment
MATERIAL: Paint Pigment
FORMULA: probalby anhydrous Co3(PO4)2
FORMULA_HTML: probably anhydrous Co3(PO4)2
COLLECTION_LOCALITY: Phillips Collection, Washington, D.C
ORIGINAL_DONOR: Patricia Favero
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Lab
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Lab
SAMPLE_DESCRIPTION:
Dry powdered paint pigment from Kremer Pigments Inc.
Visual examination in sunlight indicates this sample is light purple.
IMAGE_OF_SAMPLE:
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EPMA, ICP(Trace), WChem
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
This pigment has a number of relatively strong electronic absorptions that span the UV to NIR spectral range. The visible is dominated by two strong overlapping absorptions centered at 0.483 and 0.590 microns with weak shoulders at 0.409 and 0.676 microns. These absorptions form a moderatly strong reflectance peak centered at 0.38 microns. The NIR is dominated by four relatively broad absorptions, two of which centered at 0.865 and 1.089 microns significantly overlap. The other two at 1.642 and 2.042 microns are spatially separate. There is no evidence for water absorptions in the spectrum of this sample hense it is likely the anhydrous cobalt phosphate variety of pigment (continuum removed positions). G. Swayze
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1a2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns