Siliceous sedimentary rocks of inferior quality are typically referred to as chert. Their local use is documented at most places of occurrence but they seldom attain importance on a larger e.g. regional scale. Several raw material type groups belonging to "chert" could be separated within Hungary. Among them, Lower Jurassic Bakony chert and "Lengyel type quartzite" seem to have some, at least, regional importance. Lower Jurassic Bakony chert occurs at several plave is the Bakony Mts. It is light, off-white rosy inm colour, dull, non-transparent and rigid in appearance. Lot of sponge spicules can be observed in the material. Local exploitation can be observed at some workshop sites around the sources but the material is not known outside daily walking distance from the sources. The source of "Lengyel type quartzite" is not known exactly. It looks like some sort of quartzite but in fact it is not a metamorphic rock. Distribution data suggest that it can be probably found in the Mecsek Mts. The original rock was probably limestone very rich in fossils which became silicified later on. The rock is coarse grained, off-white and very hard, seemingly preferred for (longer) sickle-blades. It seems to be connected with Late Neolithic Lengyel culture."Nummulitovy rohovec" (silicified nummulithic limestone). Silicified nummulithic limestone served as a characteristic type of chipped stone raw material. Nummulites is a large Foraminifera (unicellular organism with calcitic shell). Its name refers to its coin-like shape. It can be as small as a lentil or as big as a palm. The surface of the shell has radial, wavy or network pattern. Nummulites lived in shallow, warm seas.