JBMA specializes in rings and jewelry handcrafted in the patterned metal technique, mokume-gane. All rings and jewelry are custom-made to a client's specifications. Each pattern is unique to that ring or piece of jewelry. … Read more JBMA specializes in rings and jewelry handcrafted in the patterned metal technique, mokume-gane. All rings and jewelry are custom-made to a client's specifications. Each pattern is unique to that ring or piece of jewelry.