Mage: The Gun Quarter
Tass is literally magic made manifest into physical form. Quintessence tends to crystallize in material form if an abundant amount of it is free flowing in an area for too long. This typically occurs in and around a Node.
Tass can take many different forms depending on the nature of the node and those who inhabit it, from coins, moss, flowers, or even bullets. These portable commodities are highly valued by mages.