The Przedkarpackie sink is a very interesting area for geological studies. These studies have a long record and focus mainly on Żupy Krakowskie (deposits of halite) due to their significance to the economic and social development of the region. Regular studies were launched as late as in the 19th century. Gypsum mined in the Kraków surroundings - Bochnia, Bonarka and Zielonki - was investigated. Gypsum from Bochnia was found to be fibrous (very pure in some cases) and concretive. On the other hand, gypsum from Bonarka is fibrous, waxy/glassy to translucent, with some clay impurities. Zielonki samples represent grey, high-crystalline gypsum.