In "Hit the Diamond", it is revealed that Yellow Diamond is in complete control of Homeworld's military. All of her subordinates have a small Yellow Diamond on their chests (except for her Pearl, as well as Doc and Navy, whose symbols are expressed differently) traditionally bordered by two symmetrically connecting diagonal black/dark outfit straps/bars. She created "the Cluster" when Earth was deemed unfit for a colony, due to the Rebellion. She is the supervisor and superior of diamond-orphaned Jasper, her expansive armies and formerly Peridot 5XG.
Blue Diamond arrived on Earth to help Pink Diamond back when Rose Quartz's rebellion only consisted of a smaller group. Sapphire was a former member of her court during this time. Following Pink Diamond's "shattering", Blue Diamond took over operations of her human zoo in an additional attempt to keep her memory alive. She was still grieving over her "passing" several millennia later, as Blue and Pink Diamond were described as being "very close."
Not much is known about her other than the fact that she was in charge of the Earth as a colony and her symbol is present on the majority of ancient Gem structures. At some point during her reign, she was--erroneously--reported to have built a human zoo, and stole humans from their families as trophies of her conquests. Her symbol is absent on later structures, such as the Pyramid Temple, as she was allegedly "shattered" by Rose Quartz towards the end of the Rebellion. Jasper was originally assigned to her as well. She also has a mural in the moon base along with all the other Diamonds. She is not present in the recent symbol for The Great Diamond Authority.
During a flashback in "Jungle Moon", Yellow Diamond was seen colonizing the orbital planet of the episode's titular location in a dream, taking on the partial appearance of Dr. Priyanka Maheswaran, while Stevonnie wholly appeared in place of Pink Diamond. The flashback shows Yellow as partially mothering and condescending of Pink and at the time wanted her to act more like a Diamond and seeming skeptical of Pink's ability to colonize at all. It is also worth noting that Pink Diamond is almost exactly as tall as Stevonnie, in contrast to the gargantuan statures of Yellow, Blue, and White Diamond.
"A Single Pale Rose" reveals Rose Quartz was in fact the same Gem as her supposed superior Pink Diamond. Wishing to be free from Homeworld's indifferent society and live with her fellow Crystal Gems alongside the life on Earth, Pink Diamond defected from Homeworld and feigned her own demise at the hand of Rose Quartz, who was actually a shapeshifted Pearl. From then, Pink would live as Rose Quartz until giving up her physical form to give birth to her son Steven.
Not much is known about White Diamond other than she is the apparent leader (or at least most senior member) of the Great Diamond Authority. As such, she is the paramount leader of all Gems including her fellow Diamonds, as well as the entirety of the Gems' intergalactic empire. She has spiky hair and her gemstone is placed on her forehead. Out of the four Diamonds, she is the largest. According to her mural, she had the most colonies when the Moon Base was built; however, it is unknown how many she has now. She wears a long white dress that reaches the floor and splits on the sides to expose her legs, shoulder pads, and a pair of intricately detailed dress sandals with high heels. She also wears a cape with black and gray stripes that is lined with diamond and star designs.
According to Pearl in "Legs From Here to Homeworld", White Diamond is not like other Gems or even her fellow Diamonds. Blue and Yellow Diamond seem to affirm this with Blue remarking she has not left Homeworld in eons and Yellow stating that in terms of power, White Diamond's far exceeds their own.
A Pearl who serves Yellow Diamond. She is arrogant and somewhat sassy, though she is only fearful of her master Yellow Diamond. She appears to uphold condescension to Yellow's troops, and seems to consider herself the power-relative vice president/second-in-command of Yellow Diamond.
A Pearl who serves Blue Diamond. This Pearl seems to be very calm and somewhat apprehensive to her owner. Blue Diamond's Pearl also acts mostly indifferent to her surroundings. She can be considered the opposite of Yellow Pearl.
A Pearl who served White Diamond. This Pearl absently gazes into the distance when speaking, bears a constant smile, remains poised en pointe and moves without physically making an effort as though she is simply floating along on her toes. In Steven's dream in "Together Alone", it is shown that White Pearl, then Pink Pearl, used to belong to Pink Diamond.
A Quartz soldier assigned to escort Peridot on her mission to Earth who participated in the first war for Earth. After attempting to build an army of Corrupted Gems to fight the Crystal Gems, she was defeated by Smoky Quartz, became corrupted, and was eventually poofed and bubbled. She was born in the Beta Kindergarten and has a defensive contempt for Earth ever since "her diamond", Pink Diamond, was said to have met an untimely end.
An Agate who, alongside Blue Diamond, manages Pink Diamond's Zoo in her absence. She also commands the various Quartzes employed there (including the group known as the "Famethyst"). Her underlings include the Earth Amethysts, the less-numerous Earth Jaspers, and (presumably) one Carnelian.
The "Ruby Squad"
A squadron of Ruby soldiers tasked with finding Jasper on Earth. While at the Barn, they are coerced into playing baseball against the Crystal Gems (posing as humans). After later searching for Jasper across the entire Solar System, the Rubies return to Earth and head to the Diamonds' Moon Base. While on the Moon, they are flung into space indefinitely, except Navy who is able to return to Earth, trick the Crystal Gems, and steal back the Roaming Eye. As revealed in "The Trial", Eyeball was rescued from space at some point and returned to Homeworld.
An Aquamarine sent to Earth by the Diamonds in order to retrieve different "variations" of humans for Pink Diamond's Zoo.
A fusion of two Topazes sent to Earth by the Diamonds in order to retrieve different "variations" of humans for Pink Diamond's Zoo.
Two Zircon Gems were appointed as legal counsel in a trial held on Homeworld. Both served as either the prosecuting or defense attorneys during the course of the proceedings. Both are "poofed" by Yellow Diamond. They have been confirmed to be still alive but "in trouble".
A massive group of small Gems who served and were created by Pink Diamond before the rebellion. Another Gem, possibly a Pebble, named Comby due to her comb-like body, serves Blue Diamond.
- Emerald: A high-ranking Emerald whose ship (the Sun Incinerator) was stolen by Lars Barriga and the Off Colors. Confirmed to be high-status aristocrat.
- Other Rubies:
- During the beginnings of the Rebellion, three Rubies (including the current Crystal Gem) are tasked with guarding a Sapphire (another Crystal Gem) only for the other two to be poofed.
- Other Quartzes:
- Several Amethysts, supervised by Holly Blue Agate, are seen guarding doors and entering Pink Diamond's Zoo in "Gem Heist" and "The Zoo".
- "The Famethyst": Amethyst meets a large friendly group of Amethysts, Jaspers, and a Carnelian in "That Will Be All".
- Rose Quartzes ("That Will Be All")
- Sixty-seven elite Citrines ("Lars of the Stars")
- A group of sixty-seven elite Citrines who are mentioned to have guarded Emerald's ship, the Sun Incinerator, on the planet Klavius 7.
- Other Unknown Gems
- Nephrite ("Bismuth")
- During the Rebellion, Bismuth mentions Pearl having fought one of Homeworld's Nephrite pilots during the Rebellion.
- The silhouetted bust of a Nephrite, specifically Nephrite-XJ Cut-763 is also depicted in Stevonnie's dream in the Jungle Moon Base in the episode Jungle Moon, while Yellow Diamond is commanding the fleet of dropships to invade the planet which the Jungle Moon orbits. Yellow Diamond scolds Nephrite and tells her that she should have been prepared cycles before then. Yellow Diamond then orders Nephrite to land the dropship fleet on the planet's surface.
- Morganite ("Off Colors")
- Rhodonite mentions an unknown commander Morganite. This Morganite at some point replaced and outcasted Rhodonite's components after discovering they liked to fuse.
- Unknown Quartz Warrior ("Sworn to the Sword")
- Blue Diamond's Court ("The Answer")
- Pink Diamond's Entourage ("The Trial")
- Emerald's crew ("Lars of the Stars")
- Nephrite ("Bismuth")
- Pink Diamond (inactive)
- Crystal Gems
- Off Colors
- Lonely Pearl
The Homeworld Gems first emerged from their home eons ago. At some point, the Homeworld Gems began to plant and grow more Gems on their home planet in order to expand their empire, draining the planet's natural nutrients. Because of this, Homeworld Gems set out to colonize other worlds under the leadership of the Diamond Authority. By the time the Homeworld Gems first set their eyes on Earth, they had already colonized 43 planetary bodies and 2 star systems.
Over 5,750 years ago, Homeworld Gems under the leadership of Pink Diamond arrived on Earth to colonize the planet. Pink Diamond came to love the life that existed on Earth, however, and so to protect the planet, she decided to repudiate her affiliation with Homeworld. She feigned her own death and would afterward adopt the physical form and persona of Rose Quartz, leader of the Crystal Gems and instigator of the rebellion to drive Homeworld off Earth.
During the Rebellion, Blue Diamond and her court arrived on Earth to stop the rebels. Due to Rose's growing army, Homeworld eventually deemed the planet as unfit for further colonization efforts and began to evacuate the Earth. The Diamonds sent one final attack: the Corrupting Light. All Homeworld Gems still evacuating were corrupted alongside the majority of the Crystal Gems.
Post-Rebellion Homeworld saw the dawn of "Era 2". Homeworld Gems produced began to lack basic Gem abilities such as shapeshifting. During this period, Homeworld Gems upgraded their technology such as light-speed space travel.
The return of "Pink Diamond" prompted the Diamonds to throw their first ball in 6,000 years, in which it was declared that "Era 3" would begin.
- Gems in alignment with Homeworld have diamond symbols on their outfits and weapons as opposed to the stars on the Crystal Gems' outfits and weapons.
- This is confirmed in the Guide to The Crystal Gems.
- The diamond symbols are colored off of whichever Diamond the Gem serves. For example, Eyeball, who serves under Yellow Diamond, wears a yellow diamond, while Holly Blue Agate, who serves underneath Blue Diamond, wears a blue diamond, and Rose Quartz, when pretending to serve under Pink Diamond, wore a pink diamond.
- There appear to be exceptions to this rule, as some Gems are known not to wear the diamond symbol, such as the Zircons, or Blue and Yellow Pearl. In the former's cases, both wear diamond-shaped ties, whereas the Pearls have diamond keyhole necklines.
- In "Gem Heist" and "That Will Be All" the Crystal Gems were able to pass off as Homeworld Gems, despite only Amethyst's outfit containing a diamond.
- Modern Homeworld Gems (or Era-2 Gems) appear to be unaware of who Pink Diamond is and events and participants of the Rebellion.
- Peridot was originally unaware of who the Crystal Gems were.
- Leggy and the other members of the Ruby Squad, except Eyeball, were completely unaware who Pink Diamond was.