Are the stones identical? Alladin's seems to have a polyhedron cut, whereas Titus' seem to be round/ovaloïd.
So the difference might really be that Alladin's is to block external rukh, when Titus' serves as a ruhk antenna, the emitter being Sheherazade as proviously hypothesed.

Regarding the Geezer, it seems he's affected by that black power which serves as manipulation medium for Al-Thamen.
Maybe being a great mage he can control it somehow. But I wonder where he really stands, when his underling was very enjoying the idea of proposing a deathmatch between Titus and Alladin.