N.K. Jemisin's Broken Earth trilogy is some of the best fantasy I've read in years- and it's also unique in being geological fantasy. Geological science fiction is certainly common enough- Hal Clement's wonderful novels, especially Mission of Gravity, are great examples. Fantasy centered around geology, however? Much, much less common.
The books center around magic users of incredible power known as orogenes (an orogeny is a mountain building event) capable of altering the Earth on a colossal scale- controlling or preventing earthquakes, for instance. Jemisin clearly put a crazy amount of time into learning geology, so that she could create a... well, scientifically plausible geological magic system. It's really, really cool, and hits the perfect level of balance between the fantastic and the concrete that so much fantasy struggles to achieve.
It's definitely a measure of my love of geology that I immediately just jump to discussing that aspect of the trilogy, however. Much more important is the incredible emotional depth of the characters and their relationships- it goes far beyond the usual level of emotional relationships in fantasy, and rather than centering around a hero and their love interest, the core emotional relationship in the series is one of anger, hurt, and betrayal- a mother who has had one of her children killed and the other kidnapped by her husband, all in the middle of the world ending- again.
Jemisin is, in my books, one of the best fantasy authors writing today. Only a handful come close to her, and only a few, such as Neil Gaiman and Patrick Rothfuss, stand alongside her in quality. She's receiving the attention she deserves, too- the first two books in the trilogy (The Fifth Season and The Obelisk Gate) won the 2016 and 2017 Hugo awards for best novel, and the third is nominated for the 2018 Hugo for best novel- I'm rooting for The Stone Sky to win as well!