Fossilization of plant remains at this site is associated with Neogene volcanic activity, ie the effects of hot silicon springs on the organic matter of wood. Chemical analyzes have shown that these fossils consist of opal (SiO2 · nH2O) and clay minerals, and paleontological analyzes have shown that they are parts of coniferous trees (mostly fir) and deciduous trees. As one of the rare sites of paleobotanical character in Serbia, Lojanik was declared a scientific research reserve with a strict protection regime back in 1963, and today it is a protected geoheritage object of the Republic of Serbia. Lojanik is at the same time important as an archeological site, because it is a prehistoric opal mine that was used as a raw material for the production of painted stone tools. That is why the experts of the National Museum in Kraljevo registered Lojanik as an archeological site in 1989.