Rhienstone was a scientist for the Homeworld aduring the Battle for Earth. He found new ways to cure different ailments and wounds, but it was never pattented, nor was it really used by regular troops, but when officers were injured, he would use this. After the battle, he was stationed on Earth to research the flora and fauna. After he found the Crystal Gems hiding out in Beach City, he joined them and started to research on different techniques of swordfighting and long-range archery, only the latter he uses. He also gained a love interest in Pearl, but he never gets around to asking her out.
Rhinestone suffers from severe gluttony, as when people interact with him, he almost always is eating, or offers them his food. He also has mild post traumatic stress disorder, as he always remembers the past, and used his rage for the patients that never survived during his operations out on his enemies. Another personality disorder he has is severe mental psychosis, as he uses several research "projects" against either his own teammates or enemies, which makes him completely unpredictable in battle