1. Oh yes, all sorts, from gardening, to fashion, to poetry and manners! There does seem to be a heavy leaning on self help magazines, interestingly enough. There isn't a limit on their cards- so go nuts!

2. It is possible if they use enough ash (and by enough we mean a LOT of ash...possible an Olympic pools size worth) they would be able to make something with a blue tinted diamond's durability and strength.

However, while this will be very confusing and will injure the ash sharks, their confusion will lead to agitation on its discovery, having them shriek for their comrades. They won't like it, and they'll try to attack it with the intention of destroying it.