A stone age setting

Imagine for a moment, a fantasy world suffering catastrophe that sends most of the world's surviving population back to the Stone Age.

Living in the stone age, the society is forced to rebuild.  It's a society where shiny gem stones are traded, and people must return to a hunter gatherer society.  Although, insular as they are, a minority of societies rediscover malachite copper and tin, forming bronze age societies.  In the interaction of these societies, you get a recipe for adventure.

This doesn't mean an RPG based on the Beastmaster.  However, it does mean an RPG that is based on the same basic idea.  The idea is only partly baked, and right now I'm doing some research to make sure everything works.  Note though, the t.v. show is badly acted.