National Museum of Minerals

The Trepca mine has yielded to museums and to collectors of all the world exceptional specimen of various minerals, particularly vivianite, ludlamite, jamesonite, pyrrhotite, arsenopyrite, dolomite et more commonly very beautiful sphalerites (marmatite). It is a giant weighing 60 millions tons ore containing 5 millions tons lead and zinc metal. Despite no fluorite has been identified there yet, the sad fate which has fallen on this famous deposit since 1990 and since the Kosovo war fully justifies one page of the website be devoted to it.

From a museological viewpoint, many of these minerals are of exceptional quality. Sphalerite marmatite, black, mostly occurs as octahedrons, with striated lustrous faces and sometimes spinel-law twinning. The crystals may reach 7 and exceptionally 10 cm in diameter, but most of them are not more than 2 to 3 cm. They are very generally associated with a calcite crystallization. A recent survey by Slovenian and German scientists showed that the twin planes [111] of sphalerite are depleted in S and enriched in O, Mn, Fe and Cu. An excess in copper generates the crystallisation of minute chalcopyrite crystals along this plane. Pyrrhotite is remarkable by its crystals of hexagonal tabular habitus reaching up to 16 cm diameter, particularly if it is not pseudomorphosed in pyrite-marcasite. It is rather rarely pseudomorphosed into galena. Galena occurs as cubes and octahedrons reaching 5 cm in edge ; it has a particular habitus characterized by corroded, eroded, melted-like faces and growing hillock structures (“flowing galena” of the german authors). Arsenopyrite often occurs as very beautiful aggregates of parallel tabular crystals, or as short prisms with [012] flat diamond-shaped faces ; the crystals are up to 5 cm in edge, but most of the collectors content themselves with a few millimetres ! Vivianite does not reach the sizes of Cameroon specimens but it forms sometimes flat prisms up to 7 and even a dozen centimetres long and 2 cm thick. It is of a very beautiful deep green. Ludlamite, apple-green, more rare, is much more appreciated. Boulangerite occurs as downy masses of very fine, fibrous, entangled crystals called plumosite ; a few needles reach 30 cm in length. Jamesonite is more rare ; the mine museum exposed a specimen where the crystals reached 4 cm long and 1.5 cm diameter. Chalcopyrite and pyrite are more banal.

It is the combination of the sulphides (with their beautiful metallic shine) with the lustrous or pearly crystals of quartz, dolomite and calcite, and with the pink ones of rhodochrosite, which confers to the specimens coming from Trep_a all their magic for the collectors. Dolomite sometimes forms beautiful rhombohedrons up to several kg in weight and 10 cm edge, associated with quartz needles. Quartz (white to hyaline) sometimes is sceptre shaped and up to 7 cm long.

From time to time, the scientists discover new species for Trep_a ; in 1995, it was the turn of a phosphate very rare in the world, childrenite (accompanied by its alteration mineral crandallite). The mineral forms free-standing doubly-terminated crystals up to 1 cm in diameter, in drusy aggregates associated with the (Mn, Fe) carbonates. It is pale yellow, dimly white in the core and more transparent and brown at the corners. The occurrence of boulangerite inclusions inside childrenite suggests that childrenite was formed under low-temperature hydrothermal conditions.  by: Jean Feraud