Well, keeping in mind the absolutely mind-boggling scale of the desert, there are innumerable oasis to congregate around, minor settlements. Most nomadic tribes keep to the north of the desert where there is more savanna than wasteland.<br/><br/>Remember: Gem is utterly incapable of supporting life. It is a mining camp made huge, and imports everything from food to water at massive expense. I doubt a nomad could gather anything of sufficient value to make using it as a supply depot fiscally viable.