Pyrite pseudomorph after Marcasite

Item Description

A rarely seen "ball" or "sphere" of Pyrite that is apparently a pseudomorph after Marcasite, from the Portland Cement Quarry in Colorado. Many modified and skeletal crystals comprise this attractive thumbnail specimen. It has great form and really nice features on every side. Hard to find and worthwhile for anybody who collects minerals of Colorado, sulfides or thumbnails.