How do the key mechanics and ideas work?
Players take it in turns performing one of three actions; mining a crystal by drawing one random crystal card, playing an action card or leaving the mine (which can provide a bravery bonus dependent on the timing of the action). At the beginning of each round a number of cards and coins are placed on the main board and these make up the bravery bonus. If players push their luck too far, accidents can occur which will result in losing all of the crystals which had been gained in that round. There are five rounds of play and after which all players count their riches to determine the winner.