NOTE: This article contains spoilers! Read with caution.
Cairngorm (カンゴーム, lit Kangōmu) is a Gem who appears midway in the story and is one of the gems who accompanied Phosphophyllite to the moon, though reluctantly. They used to be the inner shell of Ghost Quartz, who has a multilayered structure and thus two personalities. After Ghost Quartz was taken to the moon, they became active in their stead.
When Cairngorm was first introduced, their "skin" was dark and they remained so for some time in order to better feed on sunlight due to their inclusions being fickle. However, shortly after, they applied powder to their skin much like the other Gems. They wore a winter uniform, bobby socks, and a pair of black tassel loafers. They have a very short haircut that was noted to resemble Antarcticite, though Cairngorm is more combed.
Their weapon was the same sickle that had belonged to Ghost Quartz. When they took on Winter Duty, they began utilizing a weapon resembling a serrated sword, similar to the one Antarcticite used.
After Cairngorm arriving on the moon, Aechmea removes the remaining pieces of Ghost on their eyes, truly becoming themselves according to Aechmea. After this change, Cairngorm removes their powder again, returning the black skin they normally have.
Their clothing than changes away from the standard Gem uniforms to clothing designed by Lunarians that often displays a lot of skin and is white in colour. Aechmea remarks that he didn't believe that Cairngorm would choose these ones as Gems don't have any concept of sensual things.
Ghost Quartz described them as "rude, violent, selfish" as well as annoying. Ghost claims that Cairngorm was in control of their body when they recklessly climbed onto a sunspot cloud and almost got taken by The Lunarians. They seem to be very tough and strict. When they lost Ghost Quartz, they were infuriated and blamed it on Phosphophyllite, punching them several times and causing them to repeatedly need fixing from Rutile. At first, they acted harshly towards Phos. But they began to soften towards the other Gem after Phos had a breakdown and had confused Cairngorm for Antarcticite.
A few chapters into their introduction, Cairngorm began to act much kinder and gentle towards Phos and has become rather protective of them. When Phos lost their head to the Lunarians, Cairngorm even offered their former partner, Lapis Lazuli's head, to Phos. When Kongo seemed unsure of this, Cairngorm even began to offer their own head to Phos. However, during Phos's 100 year long rest period, Cairngorm reveals to Aechmea that Cairngorm wished to be crushed by the ice floes into nothingness and cease existing revealing that Cairngorm had suicidal thoughts.
After Aechmea reveals that reviving the lower hardness Gems would not be feasible, Cairngorm offered to have a synthetic outer layer attached to disguise themselves as Antarcticite and calm Phos' trauma. Aechmea questioned Cairngorm's dedication to Phos and upon examining the Gem closely, he discovered that their eyes still contained traces of Ghost Quartz which was affecting Cairngorm's behavior. He told Cairngorm to wait there while he got his tools if they wanted him to fix them. Cairngorm wanted to wait and be free, but the remnants of Ghost tried to force them to leave and remain under Ghost's influence, and the struggle caused Cairngorm to break apart. Seeing this, Aechmea understood that Cairngorm wanted Ghost Quartz removed from their eyes.
With Ghost Quartz's influence removed, Cairngorm's behavior changes drastically. They remove their powder, they don't react when Phos offers to give back Lapis's head, and they refuse to join Phos' expedition back to Earth. They also seem to have formed a close relationship with Aechmea, who encourages Cairngorm to choose a new outfit for themselves to help them regain their "sense of self."
- Has enjoyed reading just a little ever since the Ghost Quartz days. Would actually prefer the reading be done aloud by Lapis.
- Starting to get used to be forced to wear cute clothes. Stubbornly refuses to awaken to a love of them.
- Formerly on winter duty. There is a reason behind the furrowed eyebrows.
- Mega ultra super happy.
- They are first referred to as the "little one" inside of Ghost, usually by Ghost.
- They were introduced visually for the first time when their outer shell Ghost Quartz was taken to the Moon.
- They were given the name Cairngorm by Kongo-sensei.
- They teamed up with Phos and decided to go on winter duty with them.
- Phos and Cairngorm went on patrol with Peridot, Sphene, Hemimorphite, and Watermelon Tourmaline. They were attacked by the new type of Lunarian. They fought alongside with Phos, Peridot, and Sphene and were heavily damaged.
- After Phos lost their head, they offered Lapis Lazuli's head and even their own in exchange.
- Took up Winter Duty while Phos was asleep for 100+ years.
- Assisted Phos in getting purposefully captured by Lunarians to be taken by the Moon.
- Upon Phos's return, Cairngorm would prefer to just do their regular duties but is reluctantly involved with Phos's attempts to convince others to return to the Moon.
- Taken to the Moon along with Phos (the only one who goes against their will).
- Aechmea informs them in private that Cairngorm is still being controlled by Ghost Quartz because of remnants in the eyes. This is promptly removed.
- They grow closer to Aechmea, eventually developing into what seems like a romantic relationship. They also refuse to assist Phos any longer.
- They collect Phos, Yellow Diamond, and Padparadscha from a failed attack on the Earth Gems in order to speak to Sensei.
- In Chapter 75, Cairngorm is married to Aechmea in a grand ceremony. Aechmea reveals that he kept Cairngorm's arm, which Cairngorm promptly destroys.
- They express the desire to "become nothingness" with Aechmea when or if Kongo-Sensei prays. They also wish to learn science in order to learn how to becoming nothingness.
- Over 220 years of Phos missing, it's presumed that they went about their "princess" duties and weren't referred to as a Gem or as "Cairngorm" for that time span, as when Yellow Diamond calls them this, Cairn realizes only after a moment that Yellow is referring to them.
- Cairngorm is with Aechmea when Sensei begins praying again, the only Gem overhearing Aechmea speak of how Sensei praying will destroy not only the Lunarians, but the Admirabilis and Gems too. Cairngorm demands an explanation after, which isn't given.
- Cairngorm goes with Aechmea to greet the returning Phos in the ship, and is then protected by a Shiro that Cairngorm carries around when Phos attempts to attack.
- Mineral: Oxide
- Chemistry: SiO2
- Colour: brown to gray, opaque
Cairngorm is a variety of smoky quartz crystal, coming from the Cairngorm mountain range in Scotland. It usually has a smokey yellow-brown color, though some specimens are grey-brown. Smoky quartz is common and was not historically important, but in recent times it has become a popular gemstone, especially for jewelry.