To see the site where the largest amount of striped flint was mined we head to Krzemionki, 8 kilometres north-west of Ostrowiec Świętokrzyski. The Krzemionki mines were discovered in 1922 by the renowned geologist Jan Samsonowicz. The tunnels that are open to visitors are just a part of several thousand sites found in this location and, spanning 460 metres, are the largest museum route of this type in Europe. Here one can observe the mining techniques used by neolithic miners 5 – 1.6 thousand years ago. Striped flint had been a much sought after mineral for the last millennia. Its exceptional hardness, ways it can be cleaved and the possibility of producing thin, sharp chips made it the material of choice for producing all kinds of tools – axes, scrapers, arrowheads and spearheads.
Local limestone that bears flint concretions formed in the late Jurassic period (157-155 Ma), at a time when dinosaurs were at the height of their development. Calcareous mud, which was compacted into hard limestone settled in the shoals at the coast of a shallow sea, in conditions similar to those found today off the coast of Florida. The tunnels that shrimp bored in the calcareous mud were filled with substance rich in silica. What followed was a series of long chemical processes that led to the formation of flint. Items made of striped flint were not only tools of everyday use but also magic items or insignia of power and strength. They are often found in graves as a sign of the owner's high social status. Recently, there has been a renewed interest in striped flint. It has been called the “optimism stone” or the “Świętokrzyski diamond”. This time it is making its appearance as a jewellery stone worn throughout European fashion centres.