Demantoid from Kerman Province, South-east Iran: A Mineralogical and Gemmological Overview

Demantoid from Kerman Province in south-east Iran was investigated using microscopy, spectroscopy (optical absorption, FTIR and Raman), chemical analysis (EDXRF and LA-ICP-TOF-MS) and magnetic susceptibility measurements. The samples were transparent to semi-transparent and commonly contained acicular chrysotile inclusions. Their spectroscopic and chemical properties were consistent with demantoid from serpentinite host rock. The samples ranged from yellowish green to deep green, depending on Cr and Fe content. These two elements are also largely responsible for the material's paramagnetic susceptibility. Our samples contained relatively high concentrations of the trace elements Cr, Ge, Ni and Co. Comparison with available chemical data on serpentinite-hosted demantoid from the literature suggests that Iranian demantoid can be separated from stones of other localities. (c) 2022 Gem-A (The Gemmological Association of Great Britain)

Automated summary

Demantoid from Kerman Province in south-east Iran was analyzed using multiple techniques, including microscopy, spectroscopy, chemical analysis, and magnetic susceptibility measurements. The findings indicate that the samples have spectroscopic and chemical properties consistent with demantoid from serpentinite host rock. The colors of the samples range from yellowish green to deep green, depending on the levels of Cr and Fe, which also contribute to their paramagnetic susceptibility. The Iranian demantoid samples have relatively high concentrations of trace elements Cr, Ge, Ni, and Co, distinguishing them from stones of other localities.