Sardonyx has reddish-brown skin and cream-colored hair, styled into a tetrahedron with very rounded corners, similar to that of Peridot's. Her torso also greatly resembles Garnet's, but is less round. She has a white sash around her waist. As a fusion, she has four arms and inherits the same locations of her gemstones as her fused cooperators. She wears a black tailcoat tuxedo leotard with a orange bow tie and a small black star right below it. She wears two-tone reddish-gray leggings under crimson tips surrounding the top part of her feet. On her first set of arms, she wears pure white gloves that are bare on her hands, exposing them except for a pure white covering on her middle finger. On her second set of arms, located on her abdomen, she wears pure white gloves that closely resemble Sapphire's gloves, that reach to her elbows. She wears round shades that resemble Alexandrite's, but are slightly transparent and tinted with a red hue, which reveals that Sardonyx has four eyes, two on the bottom which are large and round, and two on the top which are thin, small, and narrow, all four eyes are a redeish colour. She appears to have a gap between her front teeth. Her face is rather triangular, and her feet have small light-orange diamonds on them. She is also tall and thin, similar to Pearl. Her body is also curvy, like Garnet's.
Sardonyx appears to have a combination of Garnet's and Pearl's personalities, acting very enthusiastic and upbeat while also being acutely articulate and speaking decidedly theatrically. Her mannerisms are dramatic in the theatrical sense, conversing with her peers in a matter similar to how a master of ceremonies would to her audience. She seems to be snarky and witty, often laughs at her own jokes, and remarks in a very pompous and comedic manner. She thinks very highly of herself and can be rather cocky at times, although she seems to also be considerate of other people as well as her surroundings.
Sardonyx, like the other Crystal Gems, has a positive opinion of Steven, as she interacted with Steven frequently, was happy to meet him, embraced him, and called him a "sweet little charmer". Sardonyx has shown that she does love Steven, telling him jokes and performing tricks.
Amethyst took a disliking to Sardonyx because she compares her to her own fusion with Garnet, which is very volatile and dangerous, but Sardonyx generally ignored Amethyst, instead talking to Steven.
Sardonyx possesses standard Gem abilities, including weapon-summoning, shape-shifting, bubbling, regeneration, fusion, agelessness, and superhuman strength & durability.
War Hammer Proficiency: Sardonyx can combine Garnet's gauntlets and put them on the end of Pearl's spear facing outwards to make a hammer. Her use of the war hammer is methodical in approach. She uses precise, keen strikes on specific areas to maximize damage while minimizing effort. She describes herself and therefore fighting style as "specific, intelligent, accurate, faultless, elegant, controlled, surgical, graceful, and powerful."
By rapidly spinning the top part of her hammer, Sardonyx is able to transform her weapon into a drill that could easily break through the walls of the Ancient Gem Colony Ship that Garnet's gauntlets and Pearl's spear alone could not even dent.
Anatomy Manipulation: Sardonyx has been shown to have "doll joints", body segments that have full rotation independent of the rest of her body. During her initial attack on the rebuilt Communication Hub she was seen to spin her upper body above the sash while talking to Steven, her sash arms are seen moving separate from the rest of her body throughout the scene, and during the final strike her entire body is spinning on one joint while her feet remain pointed up and immobile.
Levitation: As shown in "Cry for Help", when she was about to unleash her strike on the last pillar, she was able to hover in mid-air before descending to make her final hammer strike. She may have inherited this from Sapphire, who can levitate, or from Pearl, who momentarily levitates when battling Sugilite in Coach Steven.
Enhanced Calculations: Sardonyx is able to knock out the correct pillars to make sure the hub did not collapse until she wanted it to.
The shape of Sardonyx's hair greatly resembles that of Peridot's.
Peridot's hair, however, is more pointed and angular.
Sardonyx's debut has many callbacks to Sugilite's debut.
In Coach Steven, Garnet says, "We don't need to be careful, we just need to be huge" to justify fusing with Amethyst instead of Pearl. In "Cry for Help", Garnet tells Pearl, "What we need now is to be careful.".
When Garnet asks Amethyst to fuse in "Coach Steven", Amethyst is excited and Pearl is grumpy and disappointed. When Garnet asks Pearl to fuse in "Cry for Help", the roles are reversed.
When Sugilite forms, a red dragon silhouette appears, breathing out black flames which grow to form Sugilite's body. When Sardonyx forms, she appears in a pillar of light which turns into a curtain and then splits apart into a cloud of dragonflies.
In "Coach Steven", Steven asks Sugilite if she's going to smash things with her weapon. In "Cry for Help" Steven asks Sardonyx the same question.
Sardonyx's appearance and behavior too contrasts with Sugilite: she has Pearl's thin build (mixed with Garnet's curvaceous traits), graceful moves, well-kept hair and wears an elegant attire; also, she asked how everybody was doing just after she finished forming. Sugilite, on the other hand, has Amethyst's heavy build (again mixed with Garnet's curves), moves somewhat brutishly, has a wild hairstyle, and wears punk themed clothes; her first words after forming showed her egoist persona.
Amethyst seems very under-enthused and annoyed about Sardonyx, giving her a sarcastic "Great!" when asked how everyone was. This is similar to Pearl and Sugilite's mutual disdain towards each other.
It is the third time that Steven dubs a fusion, "Giant Woman".
Fans have noted there are many similarities between Sardonyx, and the PlatinumGames character Bayonetta. Both pose dramatically in front of the moon before performing an attack, both are classy and self confident, graceful yet incredibly strong, and both have a fondness for children (Bayonetta with Cereza & Loki, Sardonyx with Steven). They both taunt before finishing off their targets, and both have the same snarky means of addressing bystanders during battle.
Coincidentally the way Sardonyx uses her war hammer is identical to how Bayonetta uses her Hammer weapon, the Takemikazuchi, from Bayonetta 2.
Sardonyx is a type of micro-crystalline quartz, specifically onyx, banded with browns, reds, or yellows instead of black.
Onyx and sardonyx are types of agate, which is the Gemstone of those with the sign Gemini.
Sardonyx is closely related to onyx, sard, and carnelian. Banded agate with more blacks or grays is generally classified as onyx, whereas banded agate with more browns, reds, yellows, or oranges is generally classified as sardonyx. Solid red or reddish-brown agate is generally classified as sard or carnelian, depending on the shade.
Sardonyx, as with many other gemstones, can also appear as other colors, such as green and purple.
The name sardonyx itself is an amalgamation of its composition, the two minerals ‘sard’ and ‘onyx’.
Sardonyx is a gemstone of strength, protection, and victory.
Sardonyx is a stone that if carried is said to enhance willpower, vitality, confidence, stamina, integrity and optimism as well as bring happiness and stability to marriages.
Sardonyx is an alternate birthstone of August whereas the official birthstone is Peridot.
↑https://twitter.com/LeishaMedina/status/617499514295881728 "esperaremos un poco si porque será enel episodio 64.faltan bastantes semanas para su estreno pero ya conocimos a #sardonyx" rough translation: "Already seen Sardonyx, but we'll have to wait a few weeks for Episode 64" Note: She lists Keystone Motel as "episode 65", so, from the context, she clearly meant "the episode before Keystone Motel".
↑https://twitter.com/LeishaMedina/status/618478620504399872 "Nunca dije que aparecería en el 65 keystone motel. En keystone motel no sale #sardonyx ." rough translation: "I never said she'd appear in episode 65 (Keystone Motel)" Note: Keystone Motel is Episode 64 in North American airing order.