Gems are one of the most important symbols in Steven Universe. One of the ways the show foreshadowed Garnet being a fusion was that she had two gemstones instead of one, and their placement in her hand represented the fact she was made up of equals. So, looking at the protagonist of the show, Steven Universe himself, what might his gemstone symbolize?
Everything that makes up a gem is located inside their gemstone. This is why, when they are damaged, they "poof" rather than bleed. In short, gems don’t have organic bodies. So in order to have a child, Steven’s mom, Rose Quartz, had to give up her gemstone to become half of him. Any DNA that would come from his mother comes from her gemstone. This means Steven’s gemstone was once his mom’s gemstone. Right off the bat, the gemstone is the thing connecting them, this is why they both have their gemstones located on their stomachs.
While it might seem like a very small detail the gemstone location is actually very significant, too. Steven’s gemstone on his stomach replaces his bellybutton. The bellybutton is a scar that every human has left over from when they were still in utero, so the placement also represents the connection between mother and child. Steven’s gemstone is his bellybutton, his only physical connection to his mother. The show uses this as a symbol when Steven thinks of his mom, often cutting to his gem or other symbols of her, like her sword.
Humans and gems are also very different physically. For example, gems don’t age. Being half human means Steven does age, but differently than other humans. Another thing that makes gems and humans different is that gems don’t have to eat. Amethyst eats because she likes to, but any energy a gem requires comes directly from their gemstone. Steven needs to eat and the show pushes this fact a lot. Steven is shown eating in almost every episode of the first season. As an organic being, Steven’s stomach is the area he generates power, just like a gem would be. His gem is placed where his organic generator is, and they are working equally because Steven is equally gem and human.
Just like the how gemstone can change from Rose to Steven, the symbolism of it can change too. When the gemstone is on Steven it means one thing but when it is on his mother, it can mean another something else completely. The gemstone represents Steven’s energy source, with its location above his stomach, but Steven’s mother isn’t human and therefore doesn’t need to eat and this symbolism can’t apply as well to her. Instead, the gemstone is over where her womb would be, if she was human. This again connects her to Steven as it would be where baby Steven grew and developed. But the symbolism goes one step further.
A womb in itself is a symbol for life giving, and Steven possesses life-giving powers. Steven and Rose are both able to create sentient life from plants. This is a symbol that works for Rose Quartz, because she is a mother figure, and its representation is passed onto Steven along with her gemstone. While Steven isn't a mother, he exemplifies a lot of traditionally feminine traits that mother symbols tend to represent. These include: life giving powers, healing powers, empathy powers, dream powers and gardening.
Steven Universe is a beloved show because of its rich storytelling and strong visuals, and the use of symbolism is an absolute key part of that. A lot of care went into Steven's crafting, and his gem tells viewers a lot about him just from its placement.
New episodes of Steven Universe Future air Fridays at 7 PM EST on Cartoon Network. The hour-long series finale will air on March 27.