Goethite (ps after Marcasite/Pyrite)

Here's remarkable pseudomorph of goethite after marcasite/pyrite. This specimen features a stacking of two pyrite octahedron crystal forms, a distinctive specimen not often seen in the pseudomorphs from the Cretaceous Khoman Chalk of Egypt's White Desert. Originally mined by French dealer Alain Carion and his son in the remote western desert of southwest Egypt, these pseudomorphs underwent a fascinating transformation from marcasite/pyrite to iron hydroxides, primarily goethite, resulting in captivating formations.

These goethite pseudomorphs stand out for their aesthetic appeal and offer a glimpse into the dynamic world of crystallography, making them a welcome addition to any mineral collection.