Board Thread:General Discussion/@comment-12731359-20150703094912/@comment-27108464-20150707145740

What if Sardonyx is Amethyst + Steven fusion? In Onion Friend, Amethyst and Steven were supposed to be in the episode, and I expect Sardonyx to be there.

But I think Sardonyx is actually one single Gem, from another dimension (Rose/Amethyst is crystalline quartz, Jasper is non-crystalline quartz, Sardonyx is microcrystalline quartz) imitating Rose or Amethyst.