The collection of tektites, i.e. pieces of natural glass formed by the impact of meteorites on the Earth's surface, is one of the youngest collections of the department of mineralogy and petrology of the National Museum. The core of the collection was formed in 1930 with the purchase of a 1,700-piece collection of tektites – moldavites originating from all our then-known deposits – from František Hanuš, the first systematic collector of moldavites. In 1933, 506 selected specimens were exhibited in two showcases in the exhibition hall dedicated to rocks and meteorites. In 1936 the collection of Arnošt Hanisch from Třebíč was purchased, which expanded the National Museum’s collection significantly with moldavites from Moravia. In the following years, more Moravian moldavites were purchased from the collectors J. Fiala and J. Krejčí from, Třebíč. In the mid-1930s the professor of mineralogy at the Charles University, František Slavík, acquired by exchange tektites from abroad for the National Museum – indochinites from the professors of the Paris-Sorbonne University, A. Lacroix and J. Orcel, philipinites from P. Selga from Manila, and australites from Ch. Fenner from Adelaide. Between 1940 and 1942 the mineralogist Rudolf Rost started an inventory of the tektite collection. The collection of tektites of the National Museum was later expanded by its other curators: Karel Tuček, Eva Pacovská, Jiří Litochleb and Dalibor Velebil. In 1962 a significant collection of moldavites was purchased from J. Pejskar of Police nad Metují. In 1963 moldavites were obtained from the warehouses of the liquidated shop V. Frič in Prague, which traded in natural materials and teaching aids. In 1968, a collection of moldavites was purchased from the collector Emanuel Michal from Prague. Between 1968 and 1980 a large collection of moldavites was acquired from the geologist Karel Žebera. Between 1972 and 1974 a collection of moldavites was bought from B. Hrabě from České Budějovice. Other sets of moldavites and foreign tektites of various sizes were acquired from many other collectors and traders. For example, in 2001 a small set of moldavites from Dřenice in West Bohemia was bought; in 2005 large moldavites from Moravia were purchased from the estate of the collector Stanislav Langer from Hradec Králové; and in 2018 an 80-piece set of moldavites from Jakule in South Bohemia were obtained.

Currently (2018), the collection of tektites of the National Museum contains 13,891 inventory items (23,351 pieces), primarily Czech (20,800 pcs) and Moravian (1,700 pcs) moldavites; tektites from abroad make a smaller portion of the collection, in particular from Australasia (indochinites, philipinites, thailandites, billitonites, javanites, australites, tasmanites) and America (bediasites, georgiaites); and there are a smaller number of impactites (Libyan desert glass and irgizites). The moldavites in the collection of tektites form the largest public collection of moldavites in the world, which is significant not only thanks to the number of represented locations (140), but also due to the variations in their shape, colour and size. The largest South Bohemian moldavite in the collection is the specimen from Strpí weighing 111g; the largest Moravian moldavite in the collection weighs 235g and comes from Kožichovice. Among the foreign tektites, the rare 2 cm button-shaped australite stands out. There are three unique moldavites in the National Museum’s collection, found (and also thoroughly documented) in Central Bohemia; two of them come from the sand mine in Prague, Kobylisy, and one from the sand mine in Jeviněves near Mělník.