The River Kremyanka flows into the Arctic Ocean. It is located on the peninsula of Chukotka. The approximate finding zone for thundereggs is situated according to the personal report by M. Egorov at 68 ° 40' north and 169 ° 31' east. Here you'll find agate in lithophysae ("Thundereggs"). The agate can be black-brown in colour and can be found in a porphyric matrix.