Okay, ill make it short
First download any teleport hack(I cant find Mobius anymore, dont know anygood teleporter)
You teleport to DM east. get inside the instance
Teleport to the cords. X365.0427 Y254.8859 Z 109.8649, thats the coords in mobius, dont know if it is the same in others
Those coords will take you to 3 rich thorium viens wich has the drop rates
Star Ruby: 0.74%
Blue Sapphire: 0.56%
Arcane Crystal: 2.96%
Huge Emerald: 0.53%
Large Opal: 0.55%
Azethorian Diamond: 0.57%
Thorium Ore: 99.51%
Dense Stone: 40.10%
I'd say thats good drop rates, and there are 3 mines, i had 12-15 Arcane Crystals at the same run, a few runs more, you got a lot of stacks with that rare gem's ore's/bars, etc. put em on AH, and wait..
Take the exit out, do it again.
Rogues can do it stealthed with a little skill, druids could probably do it too