Faceted Garnets from Middle Part of Barakar formation, Ghugus Area, Pranhita-Godavari Basin, Maharashtra

The sandstones and siltstones of coal bearing middle part of Barakar Formation from Ghugus area of Pranhita-Godavari basin contains uniquely etched garnets characterized by smooth, hummocky, mammary facets, as well as regularly patterned, sharply faceted grain surfaces. These facets are positive features that more or less confirm with cubic and octahedral crystallographic planes of garnet structure, developed on small grains devoid of overgrowth. The lower and upper parts of this Formation on the contrary contain unetched garnets. The facets on the garnet have been attributed to etching by dicarboxylic acid, generated during the maturation of organic matter related with the burial diagenesis of the Barakar sediments.