As a fusion, Smoky Quartz adopts Steven and Amethyst's personalities. In this case, Smoky Quartz has a proud, carefree, excited, and happy-go-lucky attitude. They also have a humorous and relaxed side to their personality with a tendency to make jokes, even in the heat of battle. They restored some confidence to Amethyst, who had become depressed and unmotivated after being poofed at the hands of Jasper. Smoky does have some confidence issues, though, as they felt constant frustration when being compared to other fusions. Their humor can also be rather self-depreciating at times as well.
They are extremely confident in battle because of their cooperators' trust in one another, and as a result, they are a moderately stable fusion. However, they can defuse when under stress or intense emotion, as shown upon witnessing the beginning of Jasper's corruption.
However, as shown in "Know Your Fusion", Smoky also has both of Steven and Amethyst's self-doubts added together. In Sardonyx's attempt to find a more "serious" aspect to their fighting style outside of their yo-yo weapon, Smoky was shown to lose more and more self-confidence in themselves the more they failed at every test thrown at them. They make statements such as "zero plus zero still equals zero" and "two wrongs don't make a right, I guess I'm living proof that that's true", even going so far as to call themselves "one big super-wrong, good-for-nothing dud with a yo-yo".
Smoky Quartz has three arms (one right arm and two left arms, stemming from the same elbow joint, similar to Sugilite's), a dark mauve complexion, bushy eyebrows, and six peach freckles on their cheeks and shoulders. Their hair is a shorter version of Amethyst's. However, the color closely resembles Steven's. Their hair covers their left eye. They are slightly taller than Jasper and have a large, wide build which stems from both Steven and Amethyst. They have plump lips, a small nose, and a round face. Smoky wears two crop-top shirts, one similar to Amethyst's, and one that resembles Steven's. Steven's shirt is noticeably stretched due to Smoky Quartz's size.
Like Stevonnie, their outfit is a combination of the individual outfits of their cooperators. In their case, Smoky Quartz has a pale mauve version of Amethyst's tank top under an off-shoulder tank top that resembles Steven's shirt, along with Steven's pants, and Amethyst's dark mauve boots and leggings. The gemstones of their cooperators are located on their chest and navel.
Smoky Quartz possesses standard Gem abilities and traits, including shapeshifting, fusion, and the ability to summon a weapon.
Yo-yo Proficiency: Smoky Quartz can transform Steven's shield and Amethyst's whip into a multicolored yo-yo. They can use this to swing from and to different platforms as well as to attack opponents, and wrap it around objects. Smoky Quartz can use up to three yo-yos at once (one for each arm). It is a surprisingly versatile weapon, being a useful close range weapon and capable of extending over long distances for range attacks.
Yo-Yo Spin: Smoky Quartz can spin themselves rapidly, causing their yo-yo to swing very quickly, which can be used as an offensive maneuver.
Yo-yo Fans: Smoky Quartz is capable of spinning their yo-yo(s) with great speed, creating strong enough winds to push back a heavy-built Gem like Jasper.
Tornado Creation: With all three, even the Unknown Quartz Fusion (Jasper while fused with a corrupted Quartz) was lifted into the air, forming a mini-sand tornado in the process.
Yo-yo Grapple: Smoky Quartz can use their yo-yo(s) to grapple to objects, or to an exit.
Speed of Descent Regulation: Smoky Quartz was shown as able to land softly from a great height. In some scenes, it seems that the yo-yo assists in helping to glide across distances.
Body Spin: Smoky Quartz was shown to be able to spin like a top.
There has been limited interaction between Peridot and Smoky Quartz, but it is shown that Peridot is very supportive in their fight, attempting to use her ferrokinesis to dislodge a piece of scrap metal to help them defeat Jasper. She also cheers Smoky on and laughs when they hit Jasper with their Yo-Yo.
Upon first seeing Smoky Quartz, Jasper commented that fusion was the only tactic the Crystal Gems had. After realizing she could not win against them, she exclaimed that she would not lose against yet another fusion. Ironically, this incited her to fuse with a Corrupted Gem, which ultimately leads to her own corruption.
When Steven and Amethyst fuse to show Garnet and Pearl, they end up fusing into Sardonyx. Sardonyx leads them into a show in a room, made only when Sardonyx exists. In this show, Sardonyx tries to find something other than the yo-yo that Smoky Quartz can utilize, but, unbeknownst to her, this causes Smoky to become nervous and upset. Once Smoky starts to insult themself harshly after failing the third test, Sardonyx realizes what she has done and de-fuses in the process.
Smoky Quartz is the first known fusion between two Quartz Gems.
Smoky Quartz is also the first confirmed Crystal Gem fusion between two of the same type of Gem.
Smoky Quartz is the first fusion seen on the show that has three arms, and the first Gem to have an odd number of arms.
Smoky Quartz's left arms are not both full arms; instead, they start out as one arm before splitting at the elbow.
This could be a reference to left-handed people being considered unlucky and persecuted badly in the past, since Amethyst and Steven think so terribly of themselves.
Before Smoky Quartz was formed, a smoke mushroom cloud appeared, similar to Sugilite's Dragon and Sardonyx's Stage Curtain.
When Steven and Amethyst defuse, they phase apart. Amethyst's form converts to light like a pure Gem and Steven retains his organic form and simply splits away from Amethyst. Their voices also overlap.
Smoky Quartz's weapon is the first weapon not to be medieval themed.
Smoky Quartz's yo-yo tricks were based on yo-yo master, Tom Black's tricks from Cirque de Soleil.
Smoky quartz ranges in color from light grayish-brown to deep black.
Smoky quartz can be opaque, but is almost always transparent to translucent, even when in its darkest color shade.
Smoky quartz is a very common gemstone, with not much importance in history. Only in very recent times has it become popular.
Smoky quartz is considered an efficient gemstone for cleansing and healing. It is believed to ward off negativity.
Smoky quartz is located all throughout the world. Major deposits include Brazil, Madagascar, Mozambique, Australia, Switzerland, Scotland, and the United States of America.