Crystal Gems (Canon)

"We are the Crystal Gems! We're still alive, and we're still the guardians of this planet and all its living creatures!"

The "Crystal Gems", also referred to as the Rebels, are a group of Gems established by Rose Quartz who, unlike the rest of their kind, seek to protect the Earth instead of exploiting it and are the self-proclaimed guardians of humanity. Their title as the "Crystal Gems" distinguishes them from the Homeworld Gems.

Members

 * Garnet: The de facto leader of the group and a fusion Gem who wields a pair of gauntlets.
 * Sapphire: A calm, yet cold, Gem who makes up half of Garnet. Her weapon has yet to be seen.
 * Ruby: A short-tempered Gem and other half of Garnet. She wields a maroon gauntlet.
 * Amethyst: The carefree member of the group who wields an up to three-tailed whip. Unlike the other Gems (besides Steven, who is also from Earth), Amethyst was made on Earth, in the Kindergarten.
 * Pearl: The intellectual and precise member of the group who wields a spear. She and Rose were the first members of the group.
 * Steven Universe: The half-human member of the group who can summon a shield and a bubble, and is also the youngest. He is the son of Rose Quartz, the founder of the Crystal Gems, who gave up her physical form to give birth to him.
 * Peridot: The immature, curious, and stubborn one of the group. She is a natural-born technician and a certified Kindergartener. She was once an enemy to the Crystal Gems, but was officially accepted into the group after disobeying Yellow Diamond in "Message Received".

Known Crystal Gem Fusions

 * Opal (revealed in "Giant Woman"): A four-armed, tall and slender Gem who wields a longbow. She is the fusion of Pearl and Amethyst.
 * Sugilite (revealed in "Coach Steven"): A gigantic and bulky Gem who wields a flail. She is the fusion of Garnet and Amethyst.
 * Alexandrite (revealed in "Fusion Cuisine"): An extremely tall, six-armed fusion who has two faces and is the fusion of Garnet, Pearl, and Amethyst.
 * Stevonnie (revealed in "Alone Together"): A tall, one-quarter Gem fusion between Steven and Connie.
 * Garnet: A tough, mysterious, and very stable fusion of Ruby and Sapphire, as confirmed in "Jail Break".
 * Rainbow Quartz (revealed in "We Need to Talk") : A tall, slim, and acrobatic fusion of Rose Quartz and Pearl.
 * Sardonyx (revealed in "Cry for Help") : An upbeat and charismatic Gem who wields a war hammer. She is the fusion of Garnet and Pearl.
 * Unknown Fusion Gem: Not much is known about this fusion. It appears to have big, curly hair and has four arms. It saved William Dewey and Buddy from the Unknown Giant Gem Monster, and helped them find Beach City.

Former Members

 * Rose Quartz: Steven's mother, and the former leader and founder of the Crystal Gems who believed all life is precious.

Allied Members

 * Lion: A magical lion that joined the group in "Steven's Lion", but was revealed in "Lion 3: Straight to Video" to have a connection with Rose Quartz, which was explored more in depth in "Rose's Scabbard".
 * Greg Universe ("Laser Light Cannon", "Ocean Gem", "House Guest", "The Message").
 * Connie Maheswaran (since "Sworn to the Sword").

History
Much of the history of the Crystal Gems is shrouded in mystery. What is known is that several thousand years ago, Homeworld Gems arrived on Earth and created the "Kindergarten", a facility used to mass-produce new Gems via Injectors. This process was very invasive and damaging to the planet; the gestating Gem draining the life force out of the surrounding area in order to grow. According to Pearl, if this process was allowed to continue, the present Earth would be a lifeless, barren wasteland. Rose Quartz's empathy towards the Earth and beliefs on the Kindergarten's injustice instigated a rebellion fought by those who would become known as the Crystal Gems. Little is known about the ensuing war, simply known as The Rebellion, other than that it ended with all but a few of Rose's closest friends being destroyed, and the Homeworld Gems being driven off Earth, which was then cut off from Gem-controlled space by destroying the Galaxy Warp. For about 5,500 years, the remaining Crystal Gems have used their abilities to defend Earth from countless Gem based threats. However, Rose, as a great admirer of humanity, gave up her physical form to give birth to a half-human child, Steven Universe. The other remaining Crystal Gems, Garnet, Amethyst, and Pearl, have taken it upon themselves to raise and teach him how to use his powers.

In "On the Run", it is revealed that Rose Quartz, Pearl and Garnet originally came from the Gem Homeworld, while Amethyst was formed on Earth in a Gem Kindergarten. Amethyst is the only known Crystal Gem known to have been made in a Kindergarten.

Despite being defeated thousands of years ago, the Homeworld Gems have shown renewed interest in Earth, first sending the Red Eye (which was promptly destroyed) to scan for surviving Gems and, as of "Warp Tour", sending one of their engineers (Peridot) and her Robonoids to fix the Galaxy Warp, as well as reactivate dormant Gem technology left on Earth, such as the Facet Five in "Marble Madness" to check on the Cluster.

Rose Quartz and Pearl were shown to be the original members of the Rebellion as told in The Answer. Before Garnet joined the Crystal Gems the Rebellion has been happening for quite some time, enough for Pearl to gain a reputation as "terrifying and renegade" and that the service of a seer Sapphire was required. When Ruby was slated to be executed due to changing the future and letting the traitors escape, Sapphire saved her and the two of them decided to be Garnet and join the Crystal Gems. Sometime after the war, Amethyst was found and taken in as a member. Rose Quartz eventually gives up her physical form to bear a half human, half Gem being named Steven Quartz Universe. Peridot, a Gem loyal to Homeworld, betrays her superior Yellow Diamond in Message Received as Peridot believes Yellow Diamond is too irrational. This action allows Steven to dub Peridot a Crystal Gem with Garnet, Amethyst and Pearl agreeing.

Manifesto of Rose Quartz
The following is the Manifesto of Rose Quartz, revealed by Pearl in the Guide to the Crystal Gems:

"'Fight for life on the planet Earth,"

"Defend all human beings, even the ones that you don't understand,"

"Believe in love that is out of anyone's control,"

"And then risk everything for it!'"

Trivia

 * Instead of stars on their clothing similar to the current Crystal Gems, the Pilot versions have little gold stars pinned to themselves (Garnet's torso, Pearl's earrings, and Amethyst's hair barrette).
 * Rose seems to have been an outlier in the Gem Homeworld, as her compassion for other life forms does not seem to be shared by her fellow Gems; her fascination and love of humans was considered unorthodox.
 * The process for each Gem to summon their weapons depends on a different state of mind for each of them.
 * Amethyst places little effort or concentration, claiming that it "just happens" when she needs to summon her weapon.
 * Pearl claims her process as being perfect and calculated, using the "dance" of a flower petal in the wind to describe how hard work and dedication can help master the properties of one's own gem and "perform their own dance".
 * Garnet claims that she summons her gauntlets by linking her mind with the energy of all existing matter, channeling the collective power of the universe through her gem(s), matching her calm and meditative temperament.
 * Steven's means of summoning his shield rely on his feelings of passion or desire to protect other people/Gems, although in "Gem Glow", the joy associated with eating Cookie Cat ice cream was what summoned it. In both his "Ocean Gem" and "The Return" appearances, he summoned it when it was needed to protect those he loved from a large threat, much like his bubble in "Bubble Buddies".
 * All Crystal Gems, except for Peridot, Ruby, and Sapphire, have stars located somewhere on their outfits. It should also be noted that in the flashback in "Story for Steven", from before Rose "died", none of them had stars except for Rose herself. This may mean the Crystal Gems adopted the star in memory of Rose Quartz. The placement of the Crystal Gems' stars are as follows:
 * Steven: on his T-shirt.
 * Garnet: on the chest area of her body suit and on her gauntlets.
 * Amethyst: black star-shaped patterns on her leggings.
 * Pearl: on her top.
 * Opal: on the draping section of her shirt.
 * Rose Quartz: star-shaped cut out on the torso of her dress, showing her gem.
 * Sugilite: black and purple star-shaped patterns on her leggings and painted on her nails.
 * Alexandrite: special four-pointed star-shaped cutouts on her leggings and star-shaped hair.
 * Sardonyx: black star on the white part of her top.
 * Rebecca Sugar also confirmed that the Crystal Gems are somewhat like her, especially Pearl.
 * Amethyst is loosely based off Rebecca Sugar's friend Valerie Ang from college.
 * Rebecca Sugar confirmed that each of the Crystal Gems is based on one of the stages of the human emotional development spectrum.
 * Steven is codependent.
 * Common in most children, as children are dependent on their parents or any adult figures on practically anything and everything, as they are expected to be.
 * Amethyst is counterdependent; the explorer and rebel, fighting authority and ignoring the consequences of doing so.
 * Common in teens and young adults. People here know that they have free will; they usually distrust and challenge their superiors. This is also known as the rebellious stage.
 * Pearl is group-dependent; the responsible manager, legalistic to a fault.
 * Group-dependent people are ready on taking on responsibilities and expects others to be group-dependent as well. They tend to be obsessed with the notions of obligation and duty.
 * Garnet is independent; free to take on the burdens of others, can be a bit reckless, and is understanding of the growth that risk-taking can give as well as its limitations.
 * Tend to be merciful, and kind, and generous. They will help people because they want to, and they will not help people because they do not want to.
 * One can also argue that Rose Quartz is transcendent; kind and loving to a fault. She uses everything in her power to help those in need.
 * Master of empathy: Understanding in all situations and acts accordingly to the given situation. Merely acts to the best of their ability, understanding the limitations of their own understanding. However, in being emotionally mature, their actions tend to flow out in proper response to most any situation, expressing sympathy, anger, and forgiveness when they should.
 * All the Gems' fighting styles are based on different dances: Pearl (ballet), Garnet (waacking), and Amethyst (dancehall and club dancing). This might also have something to do with how they synchronize before fusing.
 * The rule that the Crystal Gems can't use their powers on humans was broken in "Keep Beach City Weird" when they attacked Ronaldo, but in that case an exception was probably made, since they were trying to save Steven.
 * In "Winter Forecast", it is revealed that Garnet can pass her future vision onto other Crystal Gems temporarily by giving them a kiss to the forehead. It is currently unknown whether or not if this ability is exclusive to Garnet herself, or is shared throughout the Gem race and if Gems can pass it on in different ways.
 * Each Gem has their own instrument associated with them, and these respective instruments are used in their theme music.
 * Pearl is a piano.
 * Garnet is a synth bass.
 * Amethyst is an electric drum kit.
 * Rose Quartz is a guitar, as heard in "Rose's Theme".
 * Steven is strings whenever he uses Rose's powers.
 * They can be heard in the instrumentals "Steven's Shield", "The Hill", "Overgrown Brambles", "Rose's Fountain", and "Lion's Mane".
 * In "Story for Steven", before Steven was born, the Crystal Gems were particularly asocial towards the humans of Beach City; on their half of the beach, a metal fence was up to keep humans out of that area.
 * Rose Quartz would be a considerable exception to this, as she visited other parts of the beach and saw Greg's concert, but became nervous when he insisted on following her.
 * Pearl was confused (not knowing how to make him go away) and mildly bewildered by his presence, simply referring to him as "human" or "it".
 * Amethyst asked him various questions.
 * Garnet intended to evict him from the temple as soon as she saw him, treating him as an intruder and threatening him with violence. (This was put to a halt when Rose Quartz appeared.)
 * Peridot has stated that Earth was in the Crystal System, likely where the Crystal Gems derived their name from.
 * With the exception of Steven, each of the current Crystal Gems are named after a different birthstone.
 * Garnet is the birthstone for January, while Ruby and Sapphire are the birthstones for July and September respectively.
 * Amethyst is the birthstone for February.
 * Pearl is the birthstone for June.
 * Peridot is the birthstone for August.