[ Caster looks around, catching at least one thunderous glance at them. He puts his hand on Yona's shoulder directing them— into corridor full of shelves with books, and further away from all those tables and couches for people reading them.

At least he keeps his voice low. ]

Precious stones and crystal work best. I figured how to make them with cheaper stones but— [ he rolls the runestones on the palm of his hand. ] They turn to dust after using.

[ And he neglected making spares ]