SIR Chemistry Investigation Abstract
INVESTIGATION OF JADEITE AND NEPHRITE THROUGH OPTICAL COHERENCE TOMOGRAPHY
Presenter:
Rupal Kamdar, Illinois Mathematics and Science Academy
Advisor:
Dr. William Ellingson, Argonne National Laboratory
Abstract:
Museum curators face a daunting task establishing the authenticity of a variety of important art works containing gems. Of recent interest has been the gem: Jade. Jade however is a broad term for both jadeite, NaAlSi2O6, and nephrite, Ca2(MgFe)5(OH)2(Si4O11)2. In the late Neolithic Period, the Chinese began to inter jadeite and nephrite with the deceased. Today the buried pieces are extremely costly, and therefore ascertaining if a specimen is genuine is crucial. To determine authenticity, an exploration of Optical Coherence Tomography (OCT) was performed. OCT is a newly developed, nondestructive, laser-based technology used to take cross-sectional images of the microstructure of optically translucent samples. With image resolution varying between 1-15 µm, this refraction-based system is remarkably accurate. Using OCT’s precision, previous work was conducted by researchers from the National Palace Museum of Taiwan. Their work suggests that relics have several small-scale subsurface morphologies, while forgeries have an enhanced number of large-scale morphologies. This project duplicates the Taiwanese experiment for verification, but then changes the focus to jadeite. The physical and optical properties of jadeite were explored comprehensively in an effort to conduct another experiment that would determine the authenticity of jadeite using subsurface morphologies.