Kindergarten

"Kindergartens" are a facilities that serves to create Gems by using machines called Injectors. The "Prime Kindergarten" first appeared in the episode "On the Run".

Appearance
The Kindergarten is a vast canyon with numerous holes carved out of the rock faces; these are referred to as the "birthplaces" of many Gems. Huge columns embedded with red gemstones protrude from the walls, and Injectors dot the landscape. The Injectors drilled into the Earth and implanted gems in the crust, which sucked the life out of the ground in order to incubate and form into a full Gemstone.

Background
The Kindergarten appears to be the reason why the Gems invaded the Earth, in order to exploit the Earth's resources and produce more warriors via the Kindergarten. It was once a flourishing center where Gems were grown and manufactured. If allowed to continue, it would destroy all life on Earth, as the developing Gem would incubate in the earth's crust and suck the life out of the ground. Rose Quartz saw the error in this and led a successful rebellion that caused the Homeworld to cease the production in the Kindergarten and be driven off of the Earth.

It is currently unknown what happened to the Gems produced there, but is possible that they were either destroyed, joined Homeworld, or became corrupted Gem Monsters. Some Homeworld Gems, like Amethyst, appeared to have joined the Crystal Gems. Amethyst describes the reason for her joining the Crystal Gems due to wanting the defend her birthplace.

Currently, the Kindergarten exists as a ruined canyon. There is a single Warp Pad, which can lead to any Warp Pad on Earth. The Injectors are out of use, although it should be noted that if the Kindergarten were reactivated, then they would turn on and continue the project.

"Warp Tour"
Peridot mentioned manually re-activating the Kindergarten, but was interrupted by a Flask Robonoid.

"On the Run"
Amethyst introduces Steven to this location. She reveals that she was made there, and that Gems used this place to create other "bad" Gems, or "parasites".

"Marble Madness"
The Crystal Gems follow one of Peridot's Plug Robonoids here. They destroy the power source in Facet Five, at the cost of Peridot discovering the existence of Gems on Earth. Pearl mentions Kindergarten has been inactive for 6,000 years and would destroy all life on Earth if reactivated.

"Keeping it Together"
The Crystal Gems go to the Kindergarten to search for Peridot. They find her, but she quickly escapes. Upon further investigation, Garnet discovers that Peridot wasn't trying to reactivate it, but instead she was checking on The Cluster, former Crystal Gems that Gem Homeworld shattered and forced to fuse, possibly as punishment for the rebellion.

"When it Rains"
Peridot shows Steven to the Kindergarten to give him more information about "The Cluster".

Trivia

 * "Kindergarten" means "Children's Garden" in German and usually refers to a place of preschool education. In this case, it literally means a garden where children are grown.
 * It was destroyed by the incubated Gems around 6,000 years ago, as stated by Pearl in "Marble Madness".
 * Pearl implies there are more Kindergartens then just the one on earth, or perhaps on other worlds.
 * It is unknown how many gems were grown in the Kindergarten.
 * "How Are Gems Made?" confirms that the Kindergarten had all the life sucked from it which is why it looks the way it does, foggy, lifeless, dead.
 * The person-shaped holes on the sides of the Kindergarten, as well as the manner in which Amethyst slid into hers appear to be inspired by the Junji Ito horror manga, The Enigma of Amigara Fault.
 * Amethyst also has one of the few holes at ground level. The majority are raised a great distance off the ground and much closer to the other holes where Gems were made.


 * The Injectors resemble a bacteriophage.
 * The body of the rig encases a structure that resembles an organic heart, which is attached to the head and feet via red and blue tubes resembling arteries and veins respectively.
 * The Kindergarten we currently know of was made to create Gems of the quartz variety.
 * As Amethyst is a type of quartz, this matches up with her being made here.
 * Peridot has indirectly stated that the Kindergarten has functioned atleast a few hundreds of years.