Diamond / ダイヤモンド
IMG 6299
First appearance Volume 1, Chapter 1
Episode 1
Status Inactive
Current Location Earth
Nickname Dia (ダイヤ, Daiya)
Didi (by Bort)
Race Gem
Age Unknown (same age as Cinnabar)
Hardness 10
Family The other Gems
Occupation Fighter (former)
Scout (former)
Performer (Current)
Teammate Bort (former)
Yellow Diamond (former)
Voice Actors
Japanese Ai Kayano
English Savanna Menzel
Diamond (ダイヤモンド, Daiyamondo), also called Dia, is one of the Gems who mainly does patrol duty. Despite their high offensive power, their toughness is second rate and they're easily broken. The other Gems consider them lovely and a top fashion model.


Dia has a clear, colorless scheme yet their gem's characteristic gives them a high light dispersion, thus creating rainbow reflections. They are very sparkly and blinding. They even sparkle and glow even during the night, though they seem to be able to turn this off. Their hair is a short medium bob, their eyebrows are thick and their eyelashes are long.

On Earth, they wore either a winter or summer uniform depending on the season. They also wore standard black shoes with ribbons, and white long gloves with white thigh-high socks.

On the Moon, they wear extravagant outfits that often resemble dresses with puffy skirts.


Diamond is initially very friendly, kind, and gentle. They appear to be calm during battle, even when their situation isn't good. However, they are actually insecure and frustrated with their current body which, though being the hardest, shatters easily. Dia wishes to change this. Dia dislikes being compared to Bort although they admire their younger sibling a lot.

They are perceptive regarding Gems' inner feelings and relationships, though Cinnabar accuses them of seeing everything as some kind of romance. Despite their more gentle nature, they're very stubborn and tend to be selfless and fearless in battle. From Bort's point of view, Dia is always wandering around.

Dia is shown in later chapters to be able to display hostility and a large ego.

Character Profiles

Vol. 2:

  • They want to be like Bort, and love to talk about love.

Vol. 3:

  • Cute representative. Top model.

Vol. 4:

  • Adorable. Just strong enough.

Vol. 5:

  • Cuties love cute things.

Vol. 6:

  • Very cute and relatively strong. Idol of all the gems.

Vol. 7:

  • Likes cute and pretty things.

Vol. 8:

  • Adorable. But still has worries.

Vol. 9:

  • Adorable. Adapts easily to new environments.

Vol. 10:

  • Likes it on the moon, where there are all kinds of love stories.


  • Phosphophyllite asked Diamond advice for performing better in their work, and they suggest to Phos to change what they normally do. When fighting the Lunarians, they broke their arm while trying out a new technique and threw Phos far so they could run away. Bort saved them both later and reprimanded Dia. Dia and Bort then fought the mysterious shell slug the Lunarians threw, and broke its shell.
  • Diamond mistook the slug as Phos and began looking a way to bring Phos back. Cinnabar gave them an idea and later Dia asks the Gems to pull out the shell from pond and collect Phos' fragments.
  • Dia searched for Phos in their room only to find out that Phos had placed a doll in their bed. Later they told the rest of the Gems and joined the search in the sea.
  • They joined the winter hibernation like the other Gems.
  • Phos told Dia about they became Bort's new teammate. They seemed shocked but then agreed.
  • Diamond fought the anomalous Moon Person "Shiro" and defeated it for the first time despite losing much of their body to breakage. They became sad after that because they didn't have the chance to sleep with the fluffy Moon 'People' so Red Beryl made a "Shiro" doll and gave it to them.
  • When three sunspots were spotted together at the same time, Diamond, Yellow Diamond, and Benitoite handled one together. Benitoite accidentally struck the vessel after becoming distracted by the Diamonds' bantering.
  • One of the gems who accompanied Phosphophyllite to the moon.
  • Has found their true passion of becoming a pop star on the moon.
  • Was present for Phos's return to the Moon after 220 years. Is threatened by Phos to come and destroy the Earth Gems and complies. On Earth, Dia forces Bort to fight against them. The fight ends in a draw, with both Gems shattering each other.



Diamond seems to spoil Phosphophyllite. They listen to them patiently and cares for them when they're sulking. When their blade was thrown and their arm broken, Diamond threw Phos and told them to run. It seemed because Phos tried to save Diamond's arm and got eaten, Diamond decided to look a way to bring Phos back. When they heard that Phos' plea to go to ocean got rejected, Dia planned to persuade theirSensei again together with Phos. Dia also accepted and was very understanding about Bort and Phos being teammates, and asked Phos to take care of the little one (Bort), though later they said it was so frustrating (for them). Though Dia thinks Bort is eccentric, they became upset when Phos talked badly about Bort. Along with most other gems, Dia's concern for Phos diminished after going to the moon, most likely because of their new status as a pop idol.


Their relationship with Bort is complicated: they admire and love Bort but also envy and resent them, and hopes one day to be separated from them in any way, since Bort is always getting stronger yet Diamond still feels useless in a fight despite their highest hardness. Bort thinks of Diamond's insecurities as mindless thoughts and always yells at them for their reckless and inefficient battle style, but Diamond is too stubborn to listen to them even though they know Bort is right. They once said to Phos that Bort is the real diamond. Bort sometimes calls Diamond 'Niichan'.

The other gems know about Bort and Diamond's strength situation and are kind enough to not mention it in front of Diamond. They also seem accustomed to hear them saying or doing odd things.

When apart from Bort on the Moon, Dia seems to display fear at the mention of Bort, signifying that there was more hostility in treatment from Bort towards Dia and Dia's feelings towards Bort. Phos eventually uses this to take advantage of Dia in threatening to bring Bort to the Moon so that Dia complies in assisting with destroying the Earth Gems. Dia mentions that they would like to turn that "little nuisance (Bort) into dust".


Maybe because they were 'born' in the same year, Dia is more friendly to Cinnabar and wasn't afraid being near them. They can see what Cinnabar means between words much to Cinnabar's annoyance. Diamond says that Cinnabar talks about Phos more than they talked during the last century. They also like to tease them about their 'crush' on Phos.


Morganite and Phosphophyllite once played a game against Diamond and Euclase and called them 'Team Eyebrows. Morga was also one of the gems Dia asked for help in regards of Phos turning into a slug.


Euclase and Diamond played a game of cards against Morganite and Phosphophyllite.

Gem Info

  • Mineral: Diamond
  • Chemistry: C
  • Color: Colorless

Diamond (from the ancient Greek ἀδάμας – adámas, meaning "unbreakable", "proper", or "unalterable") is one of the best-known and most sought-after gemstones. Diamond is the only gem made of a single element: It is typically about 99.95 percent carbon. The other 0.05 percent can include one or more trace elements, which are atoms that aren't part of the diamond’s essential chemistry. Some trace elements can influence its color or crystal shape. The hardness of diamond and its high dispersion of light – giving the diamond its characteristic "fire" – make it useful for industrial applications and desirable as jewelry.

It forms under high temperature and pressure conditions that exist only within a specific depth range (about 100 miles) beneath the earth’s surface. Diamond’s crystal structure is isometric, which means the carbon atoms are bonded in essentially the same way in all directions.

Perhaps the most famous use of the diamond in jewelry is in engagement rings, which became popular in the early to mid 20th century due to an advertising campaign by the De Beers company, though diamond rings have been used to symbolize engagements since at least the 15th century. Diamond is the birthstone for April. Colorless diamond is also the gem that marks the 60th and 75th wedding anniversaries. 

Source: Wikipedia | GIA


  • Diamonds have been used decoratively throughout history. In modern times, it is often associated as a gem used in weddings or marriage. This can be seen reflected in the series with Dia's own sweet and friendly personality.
  • In real life, diamond is said to be the hardest natural material on Earth. This can be compared to the character's own obstinate trait in some ways.
  • There are many types of diamonds in real life. This is also reflected in the series with the various diamond-class characters, including Yellow Diamond and Bort.
  • The hardest known type is known as Aggregated Diamond Nanorods (ADNR), which is 11% harder than bulk diamond. This type of diamond is also known to be naturally generated, rarely found in meteor impacts with graphite.


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