Among minerals from Trepča/Stari Trg, pseudomorphosis of various sulphides  e.g. pyrite, arsenopyrite, galena, chalcopyrite and marcasite after pyrrhotite are common.

Especially interesting are the oriented intergrowths of different mineral species (epitaxy), e.g. oriented intergrowth of marcasite with pyrrhotite; pyrite with arsenopyrite, barite with quartz; galena with arsenopyrite, pyrite and pyrrhotite; sphalerite with pyrite and many others.

The Trepča / Stari Trg mineral collection is very valuable due to the high level of scientific study, as part of which key mineralogical research was carried out by experts associated with our Museum and the mineralogy profession at Zagreb faculties. It represents the most valuable and mineralogically most completely processed collection of this world-famous mineralogical locality.