A rare strong rectangular crystal of pyrite with crazy perfection! Dramatic rectangles of pyrite from Spain, like this one, are 1000 times rarer than the cubes, for reasons that nobody understands. The iron content here is something like a ton per cubic matter, and it is almost all cubes. 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. Note that with matrix specimens of this material, almost uniformly the matrix is either stabilized, or the crystal repaired back into its natural place of origin (likely, both).