Pseudomorph Goethite After Marcasite | Prophecy Stone | 38 gr | Farafra Oasis, Egypt Iron some 180 m apart

some 180 m apart

It is almost round at 40x32x29mm in size

Origin: Kipawa Alkaline Complex

Here we have for you a large 39 grams superbly shaped Indochinite Tektite from Maoming City

Pseudomorph Goethite After Marcasite | Prophecy Stone | 38 gr | Farafra Oasis, Egypt Iron some 180 m apartPseudomorphs are mineral specimens that have the external shape of one mineral but are composed of another. The pseudomorph goethite after marcasite forms when marcasite is exposed to oxidizing conditions and starts to oxidize and break down. As the marcasite breaks down, goethite replaces it in the crystal structure, preserving the shape of the original marcasite crystal. The resulting specimen appears as a marcasite crystal, but is actually composed