I picked up quite a bit while killing the elementals in the Badlands. Do this quest line and you will get experience, Deeprock Salt, and Elemental Earth.
http://wow.allakhazam.com/db/quest.html?wquest=710
The Lesser Rock Elementals have a 21% drop rate.
http://wow.allakhazam.com/db/mob.html?wmob=2735#