Abstract
Lazurite, the blue mineral found in lapis lazuli, may be a marker for the identification of provenance. Sulfur K-edge X-ray absorption near edge structure spectroscopy (XANES) of lazurite from lapis lazuli of various locations, such as Afghanistan, Russia, Chile, the USA, Iran, Tajikistan, and Myanmar, is described. The XANES spectra reveal that several different sulfur chemistries exist within lazurite, attributed to contributions from multiple sulfur species. A peak at 2482.5. eV is attributed to sulfate; an envelope of peaks between 2470 and 2475. eV is attributed to polysulfide radicals, polysulfide dianions, neutral sulfur, and/or thiosulfate; and a peak at 2469.1. eV is attributed to the trisulfur and/or disulfur radical(s). Also, a peak of unknown origin arises at 2466.3. eV in several spectra. The spectral profile for the envelope of peaks (2470 to 2475. eV) varies between samples and in some instances, within a sample. Most notably, the studied samples from Chile display two distinct peaks near 2471.7 and 2473.5. eV with a local minimum at 2472.5. eV, unlike the most commonly observed pattern-that typically observed for samples from Afghanistan-with a single maximum intensity near 2472.5. eV. Other more subtle variations in this energy range also correlate with provenance at varying degrees.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 299-307 |
| Number of pages | 9 |
| Journal | Microchemical Journal |
| Volume | 125 |
| DOIs | |
| State | Published - Mar 1 2016 |
Funding
Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of EnergyOffice of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515 . The SSRL Structural Molecular Biology Program is supported by the DOE Office of Biological and Environmental Research , and by the National Institutes of Health , National Institute of General Medical Sciences (including P41GM103393). The contents of this publication are solely the responsibility of the authors and do not necessarily represent the official views of the NIGMS or NIH. Neither Stanford University, DOE, the U.S. Government, nor any person acting on their behalf: (a) make any warranty or representation, express or implied, with respect to the information contained in this document; or (b) assume any liabilities with respect to the use of, or damages resulting from the use of any information contained in the document. This project was supported by the Getty Conservation Institute (GCI) and by the Northwestern University/Art Institute of Chicago Center for Scientific Studies in the Arts (NU-ACCESS) . NU-ACCESS is funded through a generous grant from the Andrew W. Mellon Foundation . Supplemental support is provided by the Materials Research Center, the Office of the Vice President for Research , the McCormick School of Engineering and Applied Science , and the Department of Materials Science and Engineering at Northwestern University .
Keywords
- Lapis lazuli
- Lazurite
- Provenance
- Sulfur
- Ultramarine
- XANES
ASJC Scopus subject areas
- Analytical Chemistry
- Spectroscopy