Close to the Poljanska village lies the similarly-named Poljanska quarry where excavations take us back to 22 million years ago. It left rock-solid traces of a restless place, when a small lake became salty once it lost connection from the sea. Over time, it became more alkaline. Usually dolomite forms slowly, starting from limestone. But due to the lake's strange chemistry—which was uniquely rich in minerals—this time it was born in a blink of an eye, geologically speaking. But there's more: 'analcime', a rare mineral was formed when volcanic ash and the salty alkaline lake connected, truly rare!
Part of: Geosites in Papuk