Although the geological processes which cause Geodude to form are still poorly understood, they universally create a hollow, spherical geode at the pokemon's core, often filled with some gemstone or precious metal. These geodes, after their discovery a couple centuries ago, have become a target of young treasure hunters, drawn by the dream of rare gold, emerald, or platinum geodes which would leave them set for life.
Typically, they bring a fighting-type pokemon such as Machop to a nearby cave; some stronger, less pokemon-adept ones simply carry larger rocks themselves to smash the Geodude open. The individual fights are not especially difficult, but the quantities produced by individual Geodude are small, It is neither a lifelong career or the get-rich-quick scheme the hunters desire; typically they work for a few months before they give up, retire in satisfaction, or end their lives out of guilt from too many Geodude screams.
These hunts are the leading cause of death among Geodude, and pokemon rights activists would complain, were it not for the alternative. The rate of Geodude formation has actually increased in this era, and many caves are all but dominated by the rock pokemon. These hunts, for all their brutality, play a necessary role in population control which water, ice, ground, and grass pokemon are either poorly located or unwilling to provide.