Uvarovite from chromite-bearing ultramafic intrusives, Orissa, India, a crystal-chemical characterization using [sup.57]Fe Mossbauer spectroscopy

EPMA analyses of uvarovite from the chromite-hearing ultramafic intrusive of Sukinda, India, show that uvarovite containing 9.83 to 17.68 wt% [Cr.sub.2][O.sub.3] represents a solid solution of the binary uvarovite-andradite series with [Uva.sub.34-58] [And.sub.42-58]. Associated chromite grains with 57-59 wt% [Cr.sub.2] [O.sub.3] do not show any compositional variation from core to rim. [sup.57]Fe Mossbauer spectroscopic studies on the uvarovite samples undertaken both at room temperature (298 K) and low temperature (l10 K) indicate the presence of [Fe.sup.3+] only in octahedral coordination. Uvarovite grew from chromite (Cr source) and pyroxenes (Al, Fe, and Ca source) of the ultramafic host rocks. Keywords: Natural uvarovite, chromite, ultramafic intrusive, Eastern India DOI: 10.2138/am.2010.3328