Pliosaur bone fossil with striking pyrite replacement, sourced from the Volga River region of Ulyanovsk, Russia. This 7 x 1.5 x 5.5 cm specimen showcases the distinctive golden metallic luster of pyrite infilling the original bone structure, creating a dramatic contrast between the fossil's form and its mineral transformation. A rare addition to any serious mineral or paleontology collection, combining geological significance with aesthetic appeal.
