Fusion Gems

"Opal is an amalgam of our magical and physical attributes fused into a single entity."

"Fusion Gems" are the product of two or more Gems who fuse together, creating an entirely separate entity. Fusions are commonly formed in states of emergencies.

Description
When Gems fuse, both their bodies and minds become one. This creates an entirely different entity, as opposed to two minds sharing a single body. Malachite, Garnet, and Stevonnie, however, were shown to have separate thoughts, with the latter pair showing it is possible for one mind to take over the body. This is supported by Ruby and Sapphire clearly alternating dominance as Garnet in "Keeping It Together". As seen with Sugilite and Malachite, certain fusions will cause the loss of individuality between all Gems that partake if fused for too long. Garnet does explain the more abstract parts of fusion when Steven asks. Even if Ruby and Sapphire are separated, Garnet will still exist, as she is the product of their love. While all fusions require consent, a fusion of hatred has the power to run amuck and destroy.

Formation
Fusions are formed when Gems perform a synchronized dance. If successful, Gems transform into an amorphous mass of energy before fully transforming. If unsuccessful, Gems will be ejected before finishing the entire transformation. A stable fusion is shown in "We Need to Talk", when Rose and Pearl fuse into Rainbow Quartz. Garnet gives Greg a more literal explanation that Gems turn into light and has to be trusting of the other Gem with their light.

Defusion
Defusion is a process in which a fusion splits into its component Gems. An example of defusion is when Amethyst had attempted to eat, horrifying Pearl, causing Alexandrite to defuse. Another way that fusions unfuse is severe physical damage. A more stable defusion is shown in "We Need to Talk" when Rainbow Quartz unfuses by slowly shifting out of each other, instead of popping out. This is probably due to both fusees having a mutual agreement on defusing.

Appearance
Fusion Gems combine the designs of fusees. Gemstones appear in the same locations of the Gems they fused with. Each Gem involved in the fusion often contributes an additional pair of arms, showing that multiple pairs of arms are a common trait among fusions. However, Garnet and Rainbow Quartz do not display extra arms, so the appearance of extra limbs may indicate some instability in the fusion. Another common trait among fusions is having more than two eyes.

Hostility

 * "She had control when she used her power to drag their fusion into the ocean. But, a fusion like theirs is unstable, bound together by anger and mistrust. If that bond snaps, their anger will take over, and destroy."

In addition to the usual co-operative fusions, it is also sometimes possible for two opposing Gems to successfully fuse with each other, and then struggle for control without defusing. However, fusion participants run the risk of becoming overwhelmed by their shared anger and losing control.

Malachite is the only known example of a successful hostile fusion. In her case, both participants had similar motivations but conflicting goals (Jasper wanted revenge against Garnet and the Crystal Gems after her previous defeat; Lapis Lazuli wanted revenge against Jasper for imprisoning her).

Forced Fusions
Through unknown methods, it is possible to force Gemstones or Gem Shards into fusing. This method of fusion is usually incomplete, simply binding gemstones together on the edges instead of changing their colors, as shown in complete fusion. The Cluster is a result of a forced fusion, and in "Keeping it Together", it was shown that Gem Shards could be forced to fuse. The physical bodies of these Gems usually embody the incomplete fusions, with limbs being stuck together at seemingly random places.

Realms
The hostile Malachite fusion has an internal fusion realm where Lapis Lazuli and Jasper struggle for control. It is not known whether this is a general property of fusions, or an unusual property of Jasper and Lapis Lazuli's hostile fusion.

Culture

 * The Crystal Temple has the appearance of a typical fusion. The Gem placements suggest that the temple is a fusion of Rose, Amethyst, Garnet and Pearl.
 * In "Jail Break", Jasper derides fusion as a "cheap tactic to make weak Gems stronger", while Garnet states that she is a symbol of love.
 * Pearl implies fusion is rather intimate in "Coach Steven" and "Alone Together"; she tries to cover Steven's eyes while Garnet and Amethyst performed their dance, and says Stevonnie might be considered "inappropriate". In We Need to Talk, Pearl says fusion in the ultimate form of bond between Gems.

Abilities
Fusions are significantly powerful. They incorporate the powers, strengths, appearances, weapons, and abilities of both Gems.

Weapon(s)
Fusions may wield the weapons of the gems that compose them, but can combine them into a singular weapon. These weapons typically harness the abilities of the weapons that were fused. An example being, Opal's weapon, a longbow. Pearl's spear not only makes up the longbow, but the arrows are visually similar to the energy blast the spear can emit. Meanwhile, Amethyst's whip merely acts as the bowstring.

One-half

 * Stevonnie
 * Steven
 * Connie

Double

 * Garnet
 * Ruby
 * Sapphire
 * Opal
 * Pearl
 * Amethyst
 * Rainbow Quartz
 * Rose Quartz
 * Pearl
 * Malachite
 * Lapis Lazuli
 * Jasper

Triple

 * Sugilite
 * Ruby
 * Sapphire
 * Amethyst

Quadruple

 * Alexandrite
 * Ruby
 * Sapphire
 * Pearl
 * Amethyst
 * Cluster
 * 4 Former Crystal Gems

Trivia

 * First demonstrated in "Giant Woman", as of "We Need To Talk", all Gems mentioned in the show except Peridot and Yellow Diamond have been shown to fuse.
 * The dance used to fuse is a mixture of both Gems' dancing styles, which are based on their personalities.
 * Only eight fusions are currently known: Garnet, Sugilite, Opal, Alexandrite, Stevonnie, Malachite, the Cluster, and Rainbow Quartz.
 * Stevonnie is the only known hybrid-fusion.
 * There have been five successful dances, and one failed dance.
 * The first successful dance was performed by Garnet and Amethyst, forming Sugilite.
 * The second successful dance was performed by Steven and Connie, forming Stevonnie.
 * The third successful dance was performed by Ruby and Sapphire, forming Garnet.
 * The fourth successful dance was performed by Lapis Lazuli and Jasper, successfully forming Malachite.
 * The fifth successful dance was performed by Rose Quartz and Pearl, forming Rainbow Quartz.
 * The first failed dance was between Pearl and Amethyst, when they attempted to form Opal.
 * There were multiple potential dances shown in "Alone Together", but the only attempted dance was between Steven and Connie.
 * The fusion on the Crystal Temple has five gemstones, and has the most of any fusion shown thus far.
 * Forehead/Pearl
 * Chest/Amethyst
 * Palms/Garnet
 * Naval/Rose Quartz
 * It also has the most arms, but some are missing. If they were still intact, there would be eight.
 * The "Fusion Dance" displayed by gems, is very similar to the Fusion Dance shown in "Dragon Ball Z". However, the gems actually dance to fuse, rather than complete a set of poses like the Fusion Dance in Dragon Ball Z, in order to become one.
 * Fusion Gems can be separated by suffering heavy damage (Sugilite), or when one of the Gems fused disagrees with the other (Opal and Alexandrite).
 * Stevonnie seems to be an odd exception, since they separated while they were dancing in an attempt to embarrass Kevin.
 * It is unknown whether or not Stevonnie, Malachite, and Alexandrite have signature weapons.
 * Though since Connie is not a gem thus having no weapon it is assumed that Stevonnies weapon would be Stevens shield.
 * Malachite is the only fusion with two chests and four legs.
 * Alexandrite is the only fusion with six arms and two mouths.
 * Alexandrite is one of the only fusions whose dance wasn't shown.
 * Fusions can be made with humans, as shown in "Alone Together", although only Steven can do this as he is half-human.
 * With the exception of Malachite and Alexandrite, all fusions are voiced by musicians, Garnet by Estelle, Opal by Aimee Mann, Sugilite by Nicki Minaj, and Stevonnie by AJ Michalka.
 * Garnet and Stevonnie are the only known fully stable fusions.
 * Though Garnet has an extra eye.
 * Fusions combine the complexions of the Gems that form them.
 * Some of the fusion themes' names corresponds combining or fusing.
 * Opal's is called Amalgam, which is the combination of two elements to form another.
 * Sugilite's is called Synchronize, which is to act as one, or in unison.
 * Malachite's is called Collusion, which is when two parties conspire together.
 * Garnet's is called Reunion, which is the act of reuniting.
 * Fusions with more gems tend to be larger. Sugilite and Alexandrite are larger than any known two-gem fusions.
 * More stable fusions like Garnet and Stevonnie tend to be more compact and humanoid, while more volatile fusions like Sugilite, Alexandrite and Malachite tend to be larger and more monstrous.
 * However Fusions with more Gems combined can become unstable due to personalities clashing, causing unexpected and sudden defusion.
 * It is discovered by Steven and Garnet in "Keeping it Together" that the Homeworld Gems are forcing former Crystal Gems to fuse, a process which Garnet refutes as fusion, because they had not given permission to do so.
 * Jasper may have changed her mind about fusion, as first she thought of it as "a cheap tactic to make weak Gems stronger" and then she fused into Malachite to beat the Gems.
 * Stevonnie is the only fusion to have only one gemstone.