They're the youngest of the gems at 300 years old, with a hardness of just 3.5—pretty low compared to everyone else. That brittleness makes them clumsy and not exactly battle-ready, which is probably why they got stuck with what sounds like the least glamorous job around: completing an encyclopedia.
What's notable is that despite their own limitations, they care about Cinnabar, who works the night patrol and lives isolated from the rest of the gem community. They're genuinely invested in finding Cinnabar a better position, which hints at their more thoughtful side beneath all that clumsiness.
Content compiled by AnimeList.moe from publicly available sources.
