I'm a bit puzzled about these Volatile Earth. On wowhead it says they should have a droprate of 10-20% from mining noded (10% from normal and 20% from rich nodes), but I rarely get any - not nearly enough for skilling my last points in engineering.
I get many more Fire and Air and sometimes a Water, but the Earth seems to dodge me.
What's the best way to farm Volatile Earth?
Thanks a lot in advance.
Cheers