Sugilite

"Sugilite" is the Gem fusion of Garnet (and to an extent, Ruby and Sapphire) and Amethyst, and first appeared in "Coach Steven".

Appearance
Sugilite is a humongous Fusion Gem; along with equally gigantic Alexandrite she is one of the largest and tallest characters seen as of yet. She is a monstrous-looking Fusion Gem; her face features four eyes located under a strong brow and a final fifth one above it - each being a different color. Her mouth is twisted into a grin and filled with sharp, pointed teeth. She has a giant plume of spiky, dark violet hair in a style similar to Amethyst's untamed mane. Her skin color is a more pinkish shade of purple than Amethyst's, and she wears a ripped, dark purple, black and burgundy costume similar to Garnet's body suit and likewise wears a visor covering her four lower eyes. Her gems are located on her chest and on the palms of her lower hands.

Personality
Sugilite cares for herself, first and foremost. Though she carries out mission objectives, she does not do anything that she does not want to and does not hesitate to use force to achieve personal desires. She combines Garnet's headstrong, unwavering nature with Amethyst's desire to do whatever she pleases as well as her negative attitude towards authority and as such reacts badly to being told what to do by Pearl, which is a volatile mix when combined; the resulting personality is highly unstable as well as dangerous. This causes at least one dangerous situation, wherein Sugilite, enraged that she was left behind during a mission and asked to unfuse, viciously attacks and severely injures Pearl.

Despite her destructive nature, she seems to retain an attachment for Steven; she avoids targeting him directly during her rampages -- but ironically she inadvertently causes a chunk of debris to fly off and hit Steven in the face -- and wants to impress him with her strength, asking if he "Want to see something cool?" and showing him how she combines Garnet and Amethyst's weapons into her flail when he agrees.

Abilities
An absolute juggernaut in combat, Sugilite uses her sheer strength and size to overpower and crush any opposition. Her weapon is an enormous flail that uses Amethyst's whip for a rope, and Garnet's fused gauntlets as a bludgeon. Using this weapon Sugilite easily smashes through buildings, reducing a defunct Gem communications station to rubble.

Though not as acrobatic and nimble as the smaller Fusion Gem Opal, Sugilite makes up for it by sheer size; her long legs allows her to cover a lot of ground quickly and leap long distances.

Sugilite has no known weaknesses except her own reckless nature; she is only defeated when Pearl outsmarts her by luring her up the hill of the Crystal Temple and uses her spear to trip her, causing Sugilite to come tumbling down the side of the temple and comically get hit on the head by her own flail, knocking her out and ending the fusion.

Gemology
Learn more about the sugilite gemstone here.

Trivia

 * Sugilite is the first member of the Crystal Gems to act as an antagonist in the series.
 * In gemstone mythology, sugilites are known to increase balance of the mind and soul, and serves as protection from anger and negative feelings.
 * This is ironic, given Sugilite's dangerous and unstable nature.
 * It is unclear if Alexandrite or Sugilite is the largest character seen thus far; they both appear to be eight to nine times taller than Steven if you measure up to the top of their head.
 * However, if you take hairstyle into account, Alexandrite is the clear winner.
 * She is the only Gem whose namesake isn't also a birthstone.
 * Sugilite's shades bear slight resemblance to Roy Koopa's from the Super Mario Bros. series.
 * Sugilite could be based on an Oni, a Japanese demon or ogre, due to the gemstone being first discovered in Japan by Professor Ken-ichi Sugi.
 * She also strongly resembles the Hindu goddess Kali. Kali is often portrayed with four arms and a very destructive nature. Sugilite's long and somewhat wild-looking dark hair also resembles common portrayals of Kali. While Kali is often described as violent, she's still usually seen as a destroyer of evil. Some legends even show her with a caring, maternal side.
 * Sugilite demonstrates in "Coach Steven" that if multiple Gems are fused for too long, they can slowly lose their individuality in favour of the new personality of the Fusion Gem.
 * Sugilite also seems to have sugilite gemstones as fingernails faceted in different shapes. The index is shaped as a star while the rest appear to be square.
 * Sugilite is the only known Crystal Gem with three gemstones.
 * She was the first fusion Gem whose full transformation was seen on screen while Opal's transformation was interrupted and not seen, this also goes for Alexandrite.
 * The second was Garnet.
 * The third was Malachite.
 * However, Opal's and Alexandrite's fusion were shown completely while Sugilite's was short and prompt.
 * Sugilite, Amethyst, Lapis Lazuli, Alexandrite, Jasper, Malachite, Sapphire, Ruby and Peridot have not been seen bubbling away gemstones.
 * Since Sugilite has a third eye, it is possible she shares Garnet's precognition ability.
 * She's voiced by rapper Nicki Minaj.
 * This makes her the second character on the show to be voiced by a singer, the first being Estelle with Garnet.
 * She is the only Fusion Gem thus far created by the fusion between three Gems.
 * She is the only Fusion to have 5 eyes.