The Thunderegg mine which is situated at the Mount Lyall is one of the best well-known opportunities for collecting thundereggs against a fee. This offer is noticed annually of young and old. Findings are guaranteed due to the generous terraces of the area and the circumspection of the operators. The thundereggs from here are reaching sizes up to 40 cm in diameter. However the smaller specimen- approximately up to apple size, are the Thundereggs with the more beautiful, even colored patterns. 

More informations about the mine are given at www.mont-lyall.com