Goethite on Pyrite (rare Iron Cross Twin)

Item Description

This is an extraordinarily large specimen of sharp, machined looking goethite. The shape, however, is that of an iron cross twin of pyrite, which is generally very rare in nature! A single huge discovery here at this famous emerald mine changed that, and produced a large pocket of such twins. However, pieces of this size and quality were uncommon. This is a large, pristine, perfect, complete all around example weighing in at 1.2 kilos mass or 2.65 pounds in weight! It shows exceptional form and was purchased for the single crystal suite of the Meieran collection when it came out, around 2017-18. According to Google: This pyrite crystal has a very unique crystal structure referred to as an "iron-cross twin," which means a cross-symmetry is formed by two interlocking pentagonal dodecahedra. Small examples are common enough. This, however, is exceptional and shocking on a shelf, for the size and symmetry.