These Spanish pyrites constantly stop mineral newbies in their tracks, stunned, as they try to comprehend how nature could create such sharp formations. The main crystal on this aesthetic piece reaches over 4cm, with a 1.1 cm smaller cube in front. These pyrites form in very soft clay, and many of these pieces are repaired to put the pyrites back in the voids in the dry clay, as the heavy pyrites can pop out of the matrix during extraction. From the personal collection of one of the workers and preparators at the mine, who had set back a dozen fine specimens he worked on over the years and sold us the little collection recently.