Pseudomorph Goethite After Marcasite | Prophecy Stone | 44.4 gr | Farafra Oasis, Egypt Hidalgoite Its dimensions are 39x35x10 mm

Its dimensions are  39x35x10 mm

59 Grams / 9

Mined in various locations as follows: (thumbnail size)

The stones define an elliptical strewn-field measuring 7x3

At about 4

Pseudomorph Goethite After Marcasite | Prophecy Stone | 44.4 gr | Farafra Oasis, Egypt Hidalgoite Its dimensions are 39x35x10 mmPseudomorphs 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