The Slovenian Museum of Natural History in Ljubljana shelters on of the oldest historically and culturally exceptionally important collection - Zois mineral collection. It contains about 5000 specimens of minerals and rocks. The finest specimens are exhibited (only 306 specimens) and the rest are kept in depository. The collection is not important only because of its beauty and variety - after Sigmund Zois death it became the foundation stone of the Provincial Museum in Ljubljana (founded in 1821).
The original arrangement of the collection is not known. Later Zois applied Werner's classification of minerals. This system includes some materials, which do not belong to minerals (some rocks as for instance basalt). Zois refers to minerals as fossils, though of course not in the present sense of the word. Specimens originate from different parts of central and western Europe, a lot of them came from Scandinavia, Transylvania and Italy and there are also specimens from non-European countries.

ZOIS MINERAL COLLECTION - PERMANENT EXHIBITION
The minerals of Zois collection (the list of 306 exhibited minerals) are arranged by recent classification, because now it is the only exhibited mineral collection. It was renewed in 1988 (on the 100th anniversary of the recent museum building) by dr. Ernest Faninger, who wrote also a booklet Zoisova zbirka mineralov - Zoissche mineraliensammlung (trans.: Zois mineral collection).
Beside of fourteen cases filled with minerals you can see five tables, which inform you about the history of the Museum, about Zois family and about Zois mineral collection. There is also the bronze burst of Sigmund Zois (made by academic sculptor Dora Novšak), that was erected in 1971 - on the occasion of celebrating the 150th anniversary of the first museum in Slovenia.

Sigmund Zois (1747-1819) was creator of Zois mineral collection. He was well-educated owner of wholesale iron busyness and the central personality of the Enlightenment in Slovenia. In the world he is much better known as a great natural scientist, primarily a mineralogist. He was good in mineralogy, chemistry, metallurgy and mining as well as in botany and zoology. Among his correspondents we can find such prominent names as Abraham Gottlob Werner, professor of mineralogy at the famous Mining College in Freiberg, Martin Heinrich Klaproth, professor of chemistry at the University of Berlin, Peter Jordan, a professor of natural sciences at the Medical faculty of the University of Vienna, and the mineralogist Friedrich Mohs, known for his introduction of the hardness scale into mineralogy. His contemporaries held him in great esteem, which is evident from the acknowledgements bestowed upon him by renowned institutions: Gesellschaft naturforschender Freunde zu Berlin (1782), Imperialis Leopoldino-Carolina Academia Naturae Curiosum, Erlangen (1793), Academie Celtique, Paris (1806), Jenaer herzoglich = mineralogische Sozietät (1807), Wetterau'sche Gesellschaft für Naturkunde zu Hanau (1808). In 1805 a new mineral was named zoisite in honour of Sigmund Zois. Zois was awarded a high state decoration; namely the Commander's Cross of Leopold's Order (1809). He took great pains for Carniolia to get its own provincial museum. Though Zois did not live long enough to see it, soon after his death his collection of minerals became a foundation stone of the Provincial Museum in Ljubljana (founded in 1821).

When in 1804 the mineral dealer, Simon Prešern, provided Zois with specimens from Saualpe Mountains in Carinthia, Zois recognised a new up till then unknown mineral. The letters from A. G. Werner and M. H. Klaproth confirmed this fact. In 1805 A. G. Werner, in accordance with M. H. Klaproth and D. L. G. Karsten, named this mineral after Sigmund Zois, zoisite.
Nowadays, the type locality of zoisite is precisely determined: Prickler Halt on the western slope of the Saualpe Mountains in Carinthia. The area with a quarry abandoned a long time ago consists of eclogite being cut by zoisite bearing pegmatite dike.
Zoisite is a common mineral in regional metamorphosed rocks, but mostly represented in fine-grained aggregates. Reddish varieties are called thulite. Bluish zoisite crystals, which were found in Tanzania, are called tanzanite and are valuable precious stones.