Gem Homeworld

The "Gem Homeworld", or "Homeworld", is the home planet of the Gem race.

"Mirror Gem/Ocean Gem"
Lapis Lazuli states that she wanted to go home, which is Homeworld.

"Space Race"
Pearl wants to visit space again and see everything she missed while on Earth. Although she does not mention the Homeworld by name, she does mention the existence of Gem-controlled planets.

"Warp Tour"
The Homeworld is mentioned by name, and Peridot warps to Earth from the Homeworld. The Homeworld warp is repaired by Flask Robonoids in order for Peridot to arrive. Upon her departure, Garnet destroys the Warp Pad preventing travel to the Homeworld.

"On the Run"
Amethyst reveals that Homeworld Gems created other Gems in facilities known as Kindergartens for unknown purposes. Amethyst, among many others, is one of these creations.

"The Message"
Lapis Lazuli mentions that the Gem Homeworld is more advanced than what she remembered and that she doesn't understand any of it.

"The Return/Jail Break"
The Gem Warship carrying Jasper, Peridot, and Lapis Lazuli was sent from the Homeworld and was on its way back when it crashed.

Current

 * Yellow Diamond (assumed)

Former

 * Pearl
 * Garnet (Ruby/Sapphire)
 * Rose Quartz
 * Malachite (Lapis Lazuli/Jasper)
 * Peridot

Trivia

 * The Homeworld invaded Earth and set up the Kindergarten around six thousand years ago, but was driven off by the Crystal Gems' war of rebellion. Based on the numbers given, they occupied Earth for at least a thousand years.
 * The Homeworld seems to have renewed interest in Earth for reasons unknown.
 * Peridot was the first known Homeworld Gem to come to Earth since the war.
 * It is unknown if the planet has an actual name, as up to this point it has only been refered to as "The Homeworld".