These are real stones of rhyolite mined at the Petersberg in Saxony-Anhalt, Germany. It’s fascinating that each stone has its unique shape although there are countless of them existing like sand on the beach in the universe. In this collection an amont of 4 bit (2^4 = 16 pieces) of them are collected and numbered with binary numbers. Ask your search engine for rhyolite, binary numbers and don’t miscount while collecting these 4 bit bitstones from the rockchain! If you like and buy some maybe next there can be the bitstones 8 bit collection.