Houseki no Kuni (宝石の国, Land of the Lustrous) — a very remarkable manga series by Haruko Ichikawa.
Houseki no Kuni is, in essence, a tale about change caused by suffering and suffering caused by change. It follows the story of a race of immortal crystalline humanoids. The protagonist is one Phosphophyllite — brittle and somewhat disliked by their peers, they seek to figure out their purpose amidst a war with strange creatures from the Moon. This necessitates change, though at what cost... It's tempting to delve into further detail, but to spoil the series would be a mortal sin.
The chronicle of Phos' ordeal is polished with all these flourishes — the rich Buddhist symbolism and parallels, the geological trivia, the rawly expressive and ethereal artstyle (though the gems are sometimes difficult to tell apart in monochrome)...
The first chapters of the manga have a masterfully executed anime adaptation. It is one of the first series to look great despite relying on CGI — this alone makes the anime worth seeing (on top of the excellent animation, atmospheric soundtrack, and beautiful cinematography). The catch is that it makes you desperately wish for the rest of the manga to be adapted — which will only happen some ten thousand years from now.
HnK also gets bonus points for the fact that the gems are genderless and asexual — as a race of animate jewels would in theory be.
More personally speaking, Houseki no Kuni feels like precisely the sort of thing I'd wish to make if I were more talented — whether it is the symbolism, the (superficial) allusions to the natural sciences, the character designs, or the specific problems explored. Phos' tribulations resonate with my experience of the past few years (though I can't claim to have had it nearly as bad, of course!) and appeal to some sort of deep-seated desire for fundamental change and acute perception; no other work feels nearly as close to the uncreated creations I daydream about.