[Poopsi]

I think that... an important factor on the brokenness of clams is the fact that they make gem spells and sites obsolete beyond the initial gem input. After it reaches a certain size, clamming is self-supported, hence it's broken.

The same applies to the other gem producers, albeit not to the same degree (fever fetish is micromanagement hell, and blood stone requires blood slaves, which ain't alchemizable -but then again, are cheap enough for that not to matter-)