That's another weird thing. All the convocation members had stones made. We give them to Eli at the end of ShB. Azem didn't get one because he was considered a "traitor" because he/she gave up their seat. Emet then made one for Azem. So stones were a pre-sundering thing, but are they an individual thing? Each stone also has the owner's signature spell attached to them. So Did Venat then have her own stone? Prob not because she left her seat as we did.