Merlin's ring is about two inches long, in the form of a dragon. It's silver with a round, green, stone on its back.
The Dragon ring was given to Balthazar Blake by the sorcerer Merlin right before he died. Merlin made it so that Balthazar would not age before he found the Prime Merlinean, a sorcerer who would defeat the evil sorceress, Morgana le Fay. Every sorcerer has a ring. Without it, they are powerless. Balthazar traveled the world for 1,000 years looking for the Prime Merlinean. The ring would come to life, crawl around your hand and rap around your finger if you were the Prime Merlinean. After 1,000 years, Balthazar finally found the Prime Merlinean, a young boy named Dave Stutler. Dave kept the ring until college when he would become a sorcerer.