“It is that very frankness of yours that is needed for this task. I am counting on you.”
-Master Kongou to Phosphophyllite, Land of the Lustrous, Episode 1
In the first episode of Land of the Lustrous, Phosphophyllite is tasked with creating an encyclopedia for the gems. It becomes the catalyst for their transformation.. The purpose of the encyclopedia from a narrative perspective is to give Phos a push forward, and also to show how what they want to do (fight like the other gems) is at odds with what comes to them naturally due to their brittle 3.5 Mohs hardness. The encyclopedia leads Phos to Cinnabar, which in turn leads them to another self-assigned task of finding Cinnabar a new job. As soon as Phos begins to transform, the encyclopedia is all but forgotten.
However, the gems could really use an encyclopedia.
Despite Phos’ fairly rapid physical transformation, the immortal nature of the gems means that they acknowledge their own thoughts and feelings fairly slowly, if at all. This also begets an obsessive nature in many of the gems. When something in their past affects them, they latch on to a specific idea or dedicate themselves to a cause with a singular focus. As Rutile says in the first episode, it makes it difficult for them to let go. Rutile is a prime example of this: their continued dedication to reviving their partner Padparadscha inspires their extensive, and often invasive, doctor’s practice. Similarly, Phos latches onto the idea of finding Cinnabar a new job, discarding her encyclopedia assignment. Alexandrite obsessively researches Lunarians because they lost a partner to them.
When Phos first begins working on the encyclopedia — for all of one episode in their own clumsy way — there’s a discussion of what an encyclopedia actually is, and how the gems could benefit from one. Although it’s not expressly stated, Phos’ conversation with Morganite and Goshenite hints that the rest of the gems find the idea of an encyclopedia as unnecessary as Phos does, since their concerns are limited to their jobs and what is immediately is in front of them. An encyclopedia is supposed to cover and index as much knowledge as possible, but various gems like Rutile, Red Beryl, and Alexandrite are already experts in their respective fields due to the gems’ natural obsessive tendencies.
Every gem that Phos asks for help is focus on their own individual tasks — . Cinnabar is recommended as the best resource for Phos’ encyclopedia, not because Cinnabar knows all, but because they too are directionless when compared to the other gems.
With knowledge sectioned off by task, the gems also don’t seem particularly interested in what lies beyond the scope of their own jobs. Phos and Cinnabar’s curiosity come from general restlessness and internal feelings of worthlessness, respectively. Even Diamond, who wishes to change, is focused on being a more worthy partner of Bort. They’re not naturally curious.
Knowledge in Land of the Lustrous is also tricky due to the gems’ immortality. When Phos, the youngest of the group, proudly claims that they fight for Master Kongou because they love him, it reiterates that the eldest of the gems, Yellow Diamond, doesn’t even remember why they’re fighting. Not only do the gems usually keep information to themselves — for no other reason than it applies to their job only and other gems likely don’t show interest — but the more time passes in an unending life, the more likely they are to forget certain things with time, even if they haven’t been physically altered like Phos.
The more Phos uncovers through their search — first for encyclopedia information, then for Cinnabar’s new job, then for their own understanding of Master Kongou and his relation to the Lunarians — the more distrustful they become of their mentor.
Master Kongou adds another facet to the gems’ knowledge, or lack thereof. He is the one who gives Phos the job of compiling an encyclopedia, saying that it will suit Phos perfectly. Yet the act of seeking out information for this job is what eventually leads Phos to doubt Master Kongou’s words and his relationship to the Lunarians. Phos asks Cinnabar about this only to discover that the rest of their peers already know that there’s some connection between Master Kongou and their adversaries, and have decided to fight for him anyway. The gems cast their suspicions aside and the result is the cycle that Phos’ physical transformation is, at the very least challenging, if not fully breaking.
Part parent, part deity, part teacher, Master Kongou also appears mired in his own guilt, which is interesting when compared with the fact that he tasked Phos with the encyclopedia. Either he underestimated how much Phos could uncover if determined (like his potential relationship with the Lunarians) or he (consciously or subconsciously) wanted to be “caught” by one of his charges. From Phos’ flashbacks, we know that he is the one who teaches them about this world from the time that they’re gathered from the Chord Shore. This means that he could limit what information they receive from the outset. When Phos discovers that they don’t remember Master Kongou’s teachings from when they were younger, they go not to Master Kongou but to Alexandrite because what they want to know is Lunarian-specific (in order to research Master Kongou’s connection to the Lunarians).
Imagine if they had an encyclopedia where all of this — the results of Rutile’s clinical experiments, Antarcticite’s knowlege of ice floes, Alexandrite’s comprehensive Lunarian library, the nature of the Chord Shore — could be found if not in one place, then in similar proximity for points of comparison.