Another nice way to get serious gem income is to find a spell that gives you monthly gem income, then research with all your might towards that spell and cast it ASAP. Some of them are very nice, giving you like 30 gems a turn.
For magic items, I also like Blood Stones (Construction 4, 3BE). Provides +1 earth magic in addition to one earth gem per turn. Also, like fire, earth gems can be sold efficiently thru alchemy.
Aikamun
[ February 24, 2004, 23:51: Message edited by: Aikamun ]