Pseudomorph Goethite After Marcasite | Prophecy Stone | 17.9 gr | Farafra Oasis, Egypt | SO24

Pseudomorphs 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 of goethite.

The Farafra Oasis, in the White Desert, has been known for a number of years to deliver incredible pseudomorph specimens. The pseudomorphs occur within the Cretaceous Khoman Chalk, from which the White Desert derives its name.

These specimens are remarkable for their relatively sharp marcasite crystal forms in aesthetic crystal clusters. They are in excellent condition.  This collector's specimen is unique, of great quality and ready for display.

Name: Goethite After Marcasite Pseudomorph
Specimen Size:  Miniature-Sized Specimen
Dimensions:  36x28x24  mm / 1.3x1.2x1.0 inches
Weight:  17.9 grams / 0.6 ounces
Origin: Found in White Desert, Farafra Oasis, Egypt