In the Miocene marine sediments of the so-called Carpathian Foredeep, economically significant sulphur deposits have developed in both Poland and Ukraine. Native sulphur formed here from gypsum due to hydrocarbons and sulphate-reducing bacteria. While Polish mines have already been closed, there are still operating sulphur mines in Ukraine. One of them is located in Yaziv, where magnificent, even several cm sized sulphur crystals can be collected.
In the picture: Native sulphur, Yaziv (Ukraine). Crystal size: 3 cm. Photo by Viktor Jáger.