Geodes can be obtained by ascending, killing bats, finding treasure, completing the campfire quest, collecting premium daily chest, or buying them in the store.
There are 5 types of geodes from the most common to the rarest: Stone, Opal, Quartz, Magma, and Ender.
Geodes can be merged to obtain better geodes.
Opening geodes rewards the player with powerups, schmepls, and experience.