Are Clams worth empowering for?

[Hadrian_II]

I think the problem about gem producing items is that if you seriously forge them, you begin to become stronger on an exponentionally curve. But clams need other paths to forge than the gems that they produce, so they are not as stron.

Blood stones on the other hand only cost 7 earth gems, so they begin to pay for themselves really fast, maybe it would be a good idea to make them more expensive.

But i think that gem producing items give non blood nations some ability to get stronger like the blood ones (as you can hunt about as many blood slaves as you want).