Gem

Gems are a sapient extraterrestrial race with seemingly-magical abilities which hail from an extra-galactic world known simply as "Homeworld", although a large number of them has also settled on and currently reside on Earth.

Their physical bodies consist of the mineral gemstone that they all possess, which is visible in some part of their projected humanoid bodies. The location of the gemstone varies according to each individual, and the type of gemstone is determined by their caste. Dozens of different castes are known, each differing in size, basic appearance and abilities. Each caste has its own role in their rigidly hierarchical society, and its own social status.

Since their humanoid bodies are merely a projection, Gems don't age physically and can basically survive in any environment, including space vacuum. They live for millennia and can only be injured if the gemstone itself takes damage. In some circumstances, Gems may become "corrupted", compromising both their physical form (which turns into a monstrous, unrecognizable creature) and their sapience, although they may still be restored to normal if their gemstone is properly healed.

This species is also known for their ability to merge with other Gems or with Gem hybrids, producing temporary (or, if so desired, permanent) fusions. Gem/Human hybrids such as Steven Universe are even capable of fusing with normal Humans.

Biology
Individual Gems are living, intelligent gemstones that can project a tangible humanoid form. They have no heart or heartbeat, and may in fact possess no internal organs, although they can create them by shapeshifting. An x-ray of a Gem will reveal no skeletal structure and nothing other than the gemstone, although it may also show things they have consumed. Most Gems have access to superhuman powers such as shapeshifting, Gem bubbling (forming a bubble to contain smaller objects), weapon summoning or elemental control, and Gem fusion.

Gems seem to be mineral-based lifeforms due to primarily being living gemstones. A Gem's gemstone is positioned somewhere on their physical form (which is basically a solid light hologram/projection), such as the forehead, palms, chest, back or navel. The position varies from one individual to another.

Though pure Gems are referred to in feminine terms and commonly have feminine traits, Gems are a genderless race, with Steven Universe being the first male Gem to exist, as well as the first Human-Gem hybrid. Despite this, Gems with more masculine appearances and voices are not completely unheard of.

Most Gems generally take on a feminine or androgynous Human-like form, though notably distinguished by the lack of gender-defining traits such as breasts. For the most part, they appear to lack external ears, and some Gem types may lack a nose or have only one eye. The forms they take are only constructs their gemstone creates for them, which follows restrictions set by their biological caste. Their appearance varies from Gem to Gem, but their colors are mainly composed of the color palette of the gemstone they possess. If a Gem's physical form is destroyed, they will retreat into their gemstone in order to create a new form.

Most Gems are also capable of shapeshifting, but this is known to consume a lot of energy and leave a Gem exhausted when done for too long. They are functionally immortal and cannot die from old age, but can die by other means, such as being shattered. If a Gem is severely injured, their body dissipates in a burst of dust or smoke, leaving behind their gemstone, which is vulnerable and unable to move until the Gem finishes regenerating. In addition, if a Gem's gemstone is damaged, their physical form will become distorted.

Gems do not need to eat or sleep, but are nonetheless capable of doing so, and they can get physically exhausted. They're unaffected by changes in gravity, and do not need to breathe, but do appear to have functional lungs for speaking purposes, and are not immune to gasping for breath. It's not known how they digest food, though it's implied that they can simply convert it all to energy. While Gems can't die from food poisoning, they can still get sick to the point of vomiting.

Reproduction
New Gems are created from facilities called Kindergartens. While biological reproduction is an alien concept to Gems, it is not impossible for them. Although Gems can't reproduce with each other, at least one (Rose Quartz) was able to produce a Gem-hybrid offspring by shapeshifting to create a reproductive system. Her son, Steven, inherited her gemstone, without which she could not project a physical form and subsequently "died".

"Corruption"
While Gems are normally sapient, they can be become feral and animalistic in a process known as "corruption" that was caused by an attack on Earth that was intended to kill every Gem on the planet but failed. Nephrite, for instance, was formerly a normal Gem, but became a centipede-like beast when corrupted. Corruption also seems to function like a disease, and can spread through fusion, as seen when Jasper fused with a corrupted Gem she had captured to battle Smoky Quartz and eventually became corrupted as a result.

Fusions
Gems are also capable of fusing with each other in order to assume a larger and more powerful form that can comprise of two or more Gems in number. Stable fusions of up to six Gems are known to exist. The fusion forms often have more than one pair of arms (or legs in Malachite's case), and may also have multiple eyes, depending on the number of Gems the fusion is made of and the compatibility of the individuals. However, this seems to only apply to different types of Gems, as fusions of Gems of the same type do not have additional limbs.

Gems cannot fuse with Humans, but Gem-Human hybrids can fuse with Humans, as Steven did with Connie to form Stevonnie, and with Greg to form Steg. Hybrids can fuse with pure Gems too, as Steven formed Smoky Quartz with Amethyst, Rainbow Quartz 2.0 with Pearl, and Sunstone with Garnet.

Even feral, corrupted gems are capable of fusion, as Jasper fused with the corrupted Ocean Jasper to form Zebra Jasper.

A second form of fusion is known as "force-fusions" or Cluster Gems. These are very unstable, and attack non-cluster Gems to find their missing shards and become "whole" again.

Successful fusion requires harmony between the individual components. If multiple Gems stay fused for too long or have a fusion with an unstable personality, they can slowly lose their individuality as a result.

Culture and society
Gems are an intergalactic race which, 5,750 years ago, maintained several outposts on Earth, with plans to colonize the planet, but were driven off by Rose Quartz's rebellion, leaving the Crystal Gems and the corrupted Gems as the only Gems on the planet. Their empire is vast, and they're known to take over planets to obtain resources. They generally view organic life forms the same way most Humans may view plants or insects, in that they have no problem with eradicating them if this is deemed necessary.

Gem society is defined by its elaborate hierarchy and the specialization of castes. Each caste has its own place, and is expected to perform their job dutifully, show respect for their superiors and demand respect from their inferiors.

Specific high-ranking castes may demand their own specific formalities when meeting with lower-ranking Gems. The typical way for a Homeworld Gem to address a Diamond is "My Diamond" while either bowing or saluting. Sapphires are addressed as "Your Clarity" or "Your Grand Clarity" by lower castes.

Individual Gems are differentiated from other Gems of their category by identification codes based off of "Facet" and "Cut". For example, Peridot's specification is Facet-2F5L, Cut-5XG.

Gems are not biologically male or female, but use feminine pronouns for linguistic purposes, with Steven being the only male and possibly the only Gem with a gender identity at all due to his Human half. Fusions between Steven and anyone who uses "she/her" pronouns apparently use "they/them" pronouns.

Diamond
The Diamonds are the leaders of the entire race, respected by all other Gems. They're several times larger than their subjects, and their gemstones are remarkably difficult to shatter. Each Diamond has an appearance and color scheme unique to themselves.

Only four known Diamonds exist: White Diamond, Yellow Diamond, Blue Diamond, and Steven Universe, who inherited the gemstone of Pink Diamond.

Each Diamond has their own occupation: White is the head of the Diamond Authority and supreme leader of the Gem race, Yellow is the commander-in-chief of Homeworld's military, and Blue is the overseer of Homeworld's diplomacy. Pink Diamond, however, was never shown to have a particular occupation due to being (possibly) the youngest of the Diamonds.

Emerald
Emeralds are elite Gems who possess the authority to command entire fleets of spaceships. In both size and shape, they resemble young adult Humans with pale green skin, spiky dark green hair, and armored suits in various shades of green.

Sapphire
Sapphires are a specialized Gem caste with ice-based powers. They have blue or orange skin, matching-colored hair covering their singular eye, and dresses in various shades of blue or orange.

Sapphires are capable of looking into the future using a power dubbed "Future Vision", thereby serving as prophets in the Gem society.

Jade
Jades resemble Human teenagers, most of which have downturned, bridged noses, though several either lack noses or possess small upturned noses. Most Jades appear to be either yellow or green in color, but other colors of Jade do exist, such as purple, orange, red, blue, lavender, and pink.

Little to nothing is currently known about Jades, other than the fact that they appear to be ranked higher than most other Gems, but lower than Sapphires.

Lapis Lazuli
Lapis Lazulis are a specialized Gem caste with water-based powers. They physically resemble Human teenagers with thin slender bodies, light blue skin, blue hair, short flat noses, thin lips, and sundresses in various shades of blue. They utilize a pair of wings made from water for travel.

Lapis Lazulis are extremely valuable to the Gem Empire, as they are in charge of terraforming other planets to help in colonization. This is demonstrated by their ability to manipulate massive bodies of water with ease.

Nephrite
Nephrites are a one-eyed Gem caste, perhaps most well-known for their corrupted form, in which they become insectoid creatures known as Centipeetles.

Uncorrupted Nephrites resemble Human teenagers with a single large green eye, green skin, and white, dark green, or olive hair.

Nephrites serve as pilots for various types of ships and building structures on Gem colonies. Their rank is never clearly stated, but it is possible that they are high-ranking Gems because they have been known to captain their own ships.

When corrupted, Nephrites are able to produce smaller versions of themselves, generate corrosive green acid, and climb on sheer cliff faces.

Aquamarine
Aquamarines are one of the highest-ranked castes of the species. They're physically small Gems with a cherubic appearance, light-blue skin, navy blue eyes, short blue hair, and prep school-like dresses in various shades of blue. Like Lapis Lazulis, they can manifest wings made of water, though an Aquamarine's wings resemble an Earth butterfly's.

Aquamarines act as assistants to the Diamonds, as several helped with Blue and Yellow Diamond's introductions during the Era 3 ball. They can also travel to other planets to collect things that their masters want. For example, the Aquamarine the Crystal Gems met wanted to collect Steven's friends for the Human Zoo.

Topaz
Topazes are one of the highest-ranked castes of the species. They are large pot-bellied Gems with yellow skin, straight yellow hair, and maroon, mahogany, and dark brown bodysuits.

Much like Aquamarines, Topazes are assistants to Diamonds, as several helped with Blue and Yellow Diamond's introductions during the Era 3 ball. In addition, they can act as soldiers and bodyguards, similar to Quartzes.

Morganite
Morganites are a caste that has never been seen physically. Their social role is unknown, but they are ranked high enough in Homeworld's caste system to own their own Rubies and Pearls.

Zircon
Zircons are a Gem caste that have a medium rank. They stand at a rather tall height and have slim figures and long noses. They are shown to come in various colors, including blue and yellow.

Zircons act as lawyers for the judicial courts of the Gem Homeworld. For example, Blue Zircon was assigned to Steven's defense when he was on trial for Pink Diamond's shattering, and Yellow Zircon was assigned as prosecutor.

Peridot
Peridots are a specialized Gem caste with magnetism-based powers, and stand about as tall as Rubies and Sapphires physically. They have light green skin, neon green eyes, yellowish-green hair, and outfits in various shades of green. They often wear limb enhancers with artificial metallic fingers, which are not directly attached to their body, instead levitating around where the palms would be.

Peridots serve as technicians, Kindergarten managers, and maintenance workers. They are low-ranking compared to other Gems, and are only allowed into the more elite areas of Homeworld if a job is needed to be done there.

Quartz
Quartzes are a particularly diverse Gem caste that typically stands up to roughly six or seven feet (~ 1.82 - 2.13 meters) in height. Many varieties of Quartz exist, including purple Amethysts, pink Rose Quartzes, orange Jaspers, blue Agates, and red Carnelians.

When corrupted, Quartzes resemble large, eyeless wolf-like monsters with a variable amounts of horns that they often retain after being uncorrupted.

Quartzes commonly act as soldiers and bodyguards under command of both Blue and Yellow Diamond. Many of the Rose Quartzes formerly bubbled in the Human Zoo used to serve Pink Diamond prior to her defection from Homeworld.

Like other Gem types, Quartzes are able to shapeshift into many different forms. They can also roll themselves into a ball-like form for attacks.

Bismuth
Bismuths are a specialized caste that is in charge of Gem architecture. They possess a broad stature comprised of a large and bulky body type that is designed for physical labor. Their hair is styled in several dreadlocks in a mixture of several bright tones, all of which are held back by headbands.

Bismuth have been known to construct temples, spires, and arenas for higher-level Gems. Their hands are capable of fluidly changing form, without the need for typical Gem shapeshifting, to fit a wide variety of purposes. They also have above-average resistance to heat and damage, making them one of the densest types of Gem.

Ruby
Rubies are a specialized Gem caste with fire-related powers. They have bright scarlet skin, burgundy irises, dark burgundy square-shaped hair, thick builds, and outfits in various shades of red.

Rubies appear to be used as personal escorts and bodyguards for high-ranking Gems. They are considered somewhat unimportant to other Gem types and viewed as nothing more than expendable grunts, though they compensate this trait by merging with each other into fusions resembling larger versions of themselves.

Rutile
Rutiles resemble Human teenagers with tall, slender bodies, light red skin, short dark red hair, and red and maroon open-toed bodysuits.

While little to nothing is currently known about Rutiles, the Rutile Twins have been shown to have piloting capabilities.

Pearl
Pearls have slender and thin builds, pale-colored skin, light-colored eyes, pointed noses, and thin lips.

Pearls are commonly employed as servants to other types of Gems, especially the Diamonds, to the point where they are considered to be nothing more than objects.

Pebble
Pebbles are a small gray type of Gem specialized in building furniture and clothing, and often utilize shapeshifting to get tasks done, much like Bismuths.

Spinel
Spinels are a specialized Gem caste with elastic abilities. Physically, they resemble cartoon-style humanoids, with elastic bodies that allow them to distort, flatten, stretch, expand, and shrink themselves at will.

It's unknown as to the true extent of their respect on Homeworld, but they are seemingly made to be the "best friend" to their owners and entertain the higher castes, much like court jesters.

Bixbite
Bixbites are a type of Gem with a large singular eye who resemble crabs when corrupted, and can retain crab-like traits, such as claws, even after being uncorrupted.

While little to nothing is currently known about Bixbites, the Bixbite living in Beach City is skilled in precise cutting, as shown when she perfectly sliced up several pizzas. It is also possible that Bixbites act as either tactical fighters or manufacturers.

Larimar
Larimars are a small light-blue Gem caste with ice-related powers and prism-shaped heads with spikes on top.

When corrupted, Larimars resemble vaguely humanoid chunks of ice with icy-blue skin, muscular arms, hexagonal eyes, and a jagged black mouth.

According to the Crystal Gem Larimar, Larimars construct ice sculptures and statues for the Diamonds.

Obsidian
Obsidians are large black-and-white Gems with ice-based powers. According to Snowflake Obsidian, their primary function is to dig trenches and other encampments for the Gem military to use.

Spodumene
Spodumenes are tall and slender Gems with orange skin, a large singular eye, and a blue translucent coating that acts as their hair and limbs.

When corrupted, they resemble large worms with no visible eyes, a gelatinous blue coating, and a circular mouth full of sharp teeth.

Nothing is known about the Spodumenes' role in Gem society.

Tourmaline
Tourmalines are a specialized Gem caste with air-related abilities. They are large and bulky Gems with balloon-like features who resemble pufferfish when corrupted.

Nothing is known about the Tourmalines' role in Gem society, but they are capable of bouncing around using their spherical bodies. When corrupted, they can fly and spew powerful blasts of air.

"Beetle Gem"
"Beetle Gems" are an unnamed beetle-like caste. These Gems are very small in stature and have beetle-like motifs in their appearance. Some have yellow skin and pine-green hair while others have green skin and dark-grey hair.

Nothing is known about these Gems' role in Gem society.

"Water Bear"
"Water Bears" are an unnamed caste. When corrupted, they resemble tardigrades, and are made of a blue or green gelatinous substance. They have a barrel-shaped body with three stubby legs on each side, and a conical pink or grey gemstone. When uncorrupted, they appear as stout humanoids with translucent blue or green skin.

Nothing is known about these Gems' role in Gem society.

Others
"Sentient Wall Gems" are an unnamed wall-like caste which resemble polygonal walls, and have yellow skin, slab-like arms, a large, Human-like face contained in a thin pane of glass, and a rhomboidal yellow gemstone on their foreheads.

"Comby" is a small Gem shaped like a comb and somewhat resembling the Pebbles. She may belong to a highly-specialized caste or she might be a Pebble or a unique custom-made Gem created by Blue Diamond to comb her hair and sing to her. The existence of Gems like Comby suggests that extreme specialization may be normative among some of the Gems' lower castes.

History
For thousands of years, the Crystal Gems (a renegade group of Gems that reside on Earth) have used their abilities to defend Earth from magical threats. Their former leader, Rose Quartz, gave up her physical form to give birth to a half-Human child named Steven Quartz Universe. Garnet, Amethyst, and Pearl consider Steven an important member of the Crystal Gems, and the three have taken it upon themselves to raise and teach him how to use his powers.