2 Grams / 1

Its dimensions are 45x27x25 mm

It is a large specimen and is in excellent condition

Dimensions:  66x49x37mm / 2

Pseudomorph Goethite After Marcasite | Prophecy Stone | 38 gr | Farafra Oasis, Egypt Calcite 2 Grams / 1Pseudomorphs 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