Long ago, Earth was struck by six meteorites, creating six moons and leaving a lone island in their wake. Those who could not make it to the island sank to the bottom of the ocean, where, over time, they slowly turned to crystal. As countless millennia passed, 28 of these crystallized lifeforms, known as the Lustrous, rose from the depths and resided on the island. Led by the wise Kongou-sensei, they must defend themselves against the seemingly infinite number of Lunarians, inhabitants of the moons who seek to harvest their valuable bodies for crafting weapons and jewelry.

Houseki no Kuni centers around Phosphophyllite, a young gem about to turn three hundred years old. Clumsy, extremely fragile, and having no visible talent, they are one of the weakest gems around, unable to help in the fight against the Lunarians in any meaningful way. But as the battle with the otherworldly invaders rages on, they soon learn that power comes at a cost that no one should have to pay.

Houseki no Kuni ranked 10th in the 2015 Kono Manga ga Sugoi! for the Male Readers division. The series was nominated for the eighth Manga Taisho Award in 2015 and placed 13th in the final ranking.

The series was published in English as Land of the Lustrous by Kodansha USA from June 27, 2017, to November 4, 2025. It has also been released in Spanish by ECC Ediciones since September 17, 2019; in Brazilian Portuguese by NewPOP Editora since November 5, 2021; and in Polish by Studio JG since May 24, 2024.