Viz is a magical substance that takes many forms. It could be a flask of pure spring water, a newly bloomed flower, or an iridescent rock. What all these items have in common is they are infused with pure magic. Viz can be used in the casting of spells or the creation of magic items.
Viz allows a magic user to cast spells without losing it from memory. The viz is consumed in the process. One viz for a first level spell, two viz for a second level spell, three for a third level spell and so on.