Pseudomorph Goethite After Marcasite | Prophecy Stone | 30.2 gr | Farafra Oasis, Egypt | SO24 L3-6 superb shape and good size

superb shape and good size

Quartz Creek Pegmatite Mining District

Name: Eudialyte

Dimensions:  49 mm / 1

Shape:  Oval Faceted Cut

Pseudomorph Goethite After Marcasite | Prophecy Stone | 30.2 gr | Farafra Oasis, Egypt | SO24 L3-6 superb shape and good sizePseudomorphs 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