The largest natural crystal in Poland

Abstract

Gypsum crystals 0.5-3.5 m loong occurring in the Middle Miocene (Badenian) gypsum deposits in the birthern margin of the Carpathian Foredeep, are the largest mineral crystals in Poland, and represent some of the largeest natural crystals in Europe. The crystals spectacular giant intergrowth in similar to the contact 'swallow-tail' {101} twins known form other Cenozoic deposits. The intergrowths are arranged in a palisade manner and occur in a distinct stratigraphic horizon, several metres thick, that is traceable for a distance of approximately 500 km from the Czech Republic in the west to the western Ukraine in the east. In Poland its best exposures are near Busko in the Nida river valley, south of the Holy Cross Mountains, where countless gypsum crystals are 1-1.5 m in length specimens larger than 2.5 m are rare, and only one crystal approaching 3.5 m of length has been documented. This unique specimen, exposed at Bogucice-Skałki, is the largest known mineral crystal in Poland.