A large mound of lustrous, iron-tinted, pearly, curved dolomite crystals with many bladed pyrite crystals embedded in the bottom. The dolomite crystals are sprinkled with 2mm, or so, pyrite crystals. Many of the pyrite crystals have marcasite crystals formed on them in oriented overgrowth. The marcasite crystals overgrow the pyrites either totally, partially or not at all. Very interesting!