Board Thread:General Discussion/@comment-25858307-20150409220541/@comment-24986099-20150409225238

Gems can look however they want to look because their physical bodies are illusions. Also; if you remember back to So Many Birthdays, Amethyst was with Crystal Gems in an era that seemed to be at least a few hundred years ago.

Rose, Pearl, and Garnet are over 6,000 years old because that was how long ago the Gem war was. Amethyst, however, was not a participant in the Gem war and is under 6,000 years old, presumably created a short time after the Gem war because she was a product of the Kindergartens. I would assume the Crystal Gems would have shut all of them down as soon as possible after the war.

My personal estimate is that Amethyst is somewhere around 5,000 years old where the others are over 8,000.