My opinion is that, if you want the common green gems, prospect fel iron instead (easily common in hellsfire peninsula). For some reason, the gems for mithril to thorium were much harder to get than the gems from fel iron. As I recall though, maybe it’s because there were *many* times of getting nothing from mithril and thorium, whereas starting with fel iron, you seem to get more of 2-3 gems.
But if you want the bigger chance for blue gems, prospect on adamantite. Also, this results in the adamantite dust which you’ll need for other recipes later, so you have multiple reasons to do it for adamantite even if you can get green gems on fel iron.
Edited, May 14th 2007 5:33pm by bluegayle