Sulphur deposits have often developed in the Miocene sediments of the so-called Carpathian Foredeep (about 14 million years old), especially in the Tarnobrzeg region. The most significant of these is located in the vicinity of Machów, where sulphur was mined between 1964 and 1993. Here, the native sulphur is often accompanied by columnar or needle crystals of celestine (strontium sulphate, SrSO₄) up to several cm long. Although there is no economic benefit to this mineral here, the most beautiful celestines of many of the world’s mineral collections come from this site.
 In the picture: Clestine, Machów (Poland). Size: 16 cm. Photo by Géza Kulcsár