What is Garnet's real name?

Garnets as their own gems(not fusions) exist, they do not appear in the show, but they have a part in the lore. Garnet we know technically isn't garnet, Blue Diamond makes fun of it that she calls herself one, so what's ''Garnet's'' real fusion name?

And since we're talking about this, do such gems as Opal (pearl + amethyst) exist in the lore as their own gems and not fusions? It confuses me that different gems combine into one gem, like opal, but do opals exist as their own gems in their universe?