I have found a few of these in chapter 2 and I was wondering if they have any other use than their enormous 1 gp value.

Only if you can create magic items.

Any ideas on about how many I should keep around?

They have another use to, and that's to gain access to the inventory of a certain merchant, but that won't really matter unless you're a mage. I usually keep around all that I find with my cleric, even though I end up with more than I use. I'd say 5 should be more than enough.

ok i'll keep around 5.