Gemworld is a world located in a dimension which was originally owned by the Lords of Chaos. However, thousands of years ago, when magic began to drop in its levels on Earth due to a change in the alignment of the stars (caused by a star going nova) the Homo magi sorceress Citrina went there and struck a deal with the Lords of Chaos so she would be allowed to create a realm there for those Homo magi and Faerie who wanted to emigrate from Earth. This deal was kept a secret from most of Gemworld's inhabitants.
Gemworld was rule by 12 royal Houses of Gemworld. The most prominent among them was Amethyst's family, the House of Amethyst, the most powerful magic users in all of Gemworld. They were the natural rulers until Dark Opal arose and slew Amethyst's parents. For the next 20 years Dark Opal ruled Gemworld until finally being overthrown by an alliance of the other 11 Houses, led by Amethyst.