Spectroscopic characterization of fluorite of Amba Dongar, Gujarat, India: Linking chemical composition with color.

This work addresses the long-standing debate surrounding the origin of color variation in fluorite (CaF) through a novel quantitative approach. By examining eight carefully selected fluorite samples having different hue of colors from the Amba Dongar mine in Gujarat, India, a rigorous quantitative analysis was conducted. This approach combined chemical compositional data and optical spectroscopic features to elucidate the relationship between elemental composition, concentration, and color variation in fluorite.

Natural Fe-bearing aluminous bridgmanite in the Katol L6 chondrite.

Bridgmanite, the most abundant mineral of the Earth's lower mantle, has been reported in only a few shocked chondritic meteorites; however, the compositions of these instances differ from that expected in the terrestrial bridgmanite. Here, we report the first natural occurrence of Fe-bearing aluminous bridgmanite in shock-induced melt veins within the Katol L6 chondrite with a composition that closely matches those synthesized in high-pressure and temperature experiments over the last three decades. The Katol bridgmanite coexists with majorite and metal-sulfide intergrowths.

Astrobiological implications of dim light phototrophy in deep-sea red clays.

Red clays of Central Indian Basin (CIB) under influence of trace of Rodriguez Triple Junction exhibited chemoautotrophy, low temperature hydrothermal alterations and photoautotrophic potential. Seamount flank TVBC-08, hosting such signatures revealed dominance of aerobic anoxygenic phototroph Erythrobacter, with 93% of total 454 pyrosequencing tags. Subsequently, enrichments for both aerobic (Erythrobacter) and anaerobic anoxygenic phototrophs (green and purple sulphur bacteria) under red and white LED light illumination, with average irradiance 30.