I have always found it fascinating that there is only one spot on the whole huge Earth of ours, where these stones are excavated, Świętokrzyskie region as mentioned. It is called sometimes "Polish diamond", or 'stone of optimism' as some believe wearing it makes one more optimistic I'm not sure but it it surely very beautiful.
This is truly beautiful. I live in a village named Flint Hill but the flint we find here is in ugly nodules ranging from light brown to black in colour. During the Stone Age it was successfully used to make tools and weapons but it is useless for anything else and has no natural beauty.
In Derbyshire (about 200 Km from here) we have Blue John, which has been found nowhere else on the planet. This is a beautiful mineral which has been used to make itemsas small as ear rings up to large ornamental urns. I can't post a picture but I can give you a link