i'm so sorry if the answer is obvious but before my hiatus i was collecting them, what are their primary purpose? certainly not just for crystal shards?

you can collect one of each and get an Achievement, or you can sometimes be lucky and not get a shard and get a tome instead. Tomes are nice stat-boosters. Or, you can sell either the Mage Ams or the Tomes..

oh yeah it was for tomes! thanks!

you are welcome.