Lepediolite

Perma-Fusion of 3 gems; a Ruby, Amethyst, and Pearl

Member of the Exes, she's fun-loving and always down for anything, but has a violent streak in her from years of abuse and the corruption still inside her. Ruby was healed by Yellow Diamond, but some scars go deep.

During the war, Amethyst and Ruby were inseparable fighters. They didn't so much care about the Earth as care about staying together - and as two different gems, that was impossible on Homeworld, so they eventually joined the rebellion. At some point, the two were separated, and lost each other. In the final moments on Earth, Amethyst made the decision to turn back to Homeworld - the Diamonds blasted the planet, but Amethyst got off in time to pass herself off as a Homeworld gem. She returned to Homeworld and was given a new assignment. Ruby, however, got trapped in the blast and corrupted, turning into a beast that roamed  a thick jungle.

Back on Homeworld, Amethyst was full of guilt at her decision. She was given a new assistant as a personal guard to an aristocratic gem. There were several other Amethysts assigned to her, but Amethyst couldn't relate to them, being that she was a rebel. Eventually, she confided in her master's Pearl - after a lot of coaxing to friendship. Pearl revealed that she hated being on Homeworld too, and she hated being a decoration. The two fell in love, but remained separate to keep it secret.

After the events of Steven Universe, Amethyst and Pearl were released to do whatever they wanted. Guiltily, Amethyst admitted she wanted to go find Ruby. Pearl agreed to go with her, knowing it was important to her. She went to the last place she remembered seeing Ruby, a dense jungle, and was shocked at what she found there. Amethyst and Pearl together defeated and bubbled Ruby, bringing her back to the Diamonds to be fixed. It took a long time, what with all the other gems needing fixing, but eventually Ruby was back with them. They reconnected, let each other know what happened while they were separated, and eventually the three of them became an inseparable team.

They are now a perma-fusion, in order to never be separated again.