Katerina Evanthia Custom Jewelry Designer in San Diego, CA - Custom Jewelry That Tells Your Story. For over twenty years, Katerina Evanthia has been transforming precious metals, diamonds and gemstones into compelling hand-crafted jewelry. Inspired by her Greek heritage and educated in sculpture, metalsmithing, CAD, art history, she has an innate ability to capture complex design concepts, and the aesthetics of emotions into jewelry.