Pseudomorph Goethite After Marcasite | Prophecy Stone | 30 gr | Farafra Oasis, Egypt | SO24 Pseudomorph Name: Stilbite Crystal

Name: Stilbite Crystal

Name: Okenite with Gyrolite on Quartz and Prehnite Druse Crystal

This impactite was formed 186 million years ago

Dimensions: 99x99x87 mm / 3

Product ID: TZIM6819

Pseudomorph Goethite After Marcasite | Prophecy Stone | 30 gr | Farafra Oasis, Egypt | SO24 Pseudomorph Name: Stilbite CrystalPseudomorphs 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