Goethite (ps after Marcasite/Pyrite)

Here's remarkable pseudomorph of goethite after marcasite. This specimen features sharp marcasite crystal forms, a distinctive trait no always common in pseudomorphs from the Cretaceous Khoman Chalk of Egypt's White Desert. 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 to iron hydroxides, primarily goethite, resulting in captivating radial bursts.

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.