The Spirit Ring is loosely based on Agricola's De re metallica, as well as on a folk tale, and the life of Benvenuto Cellini, as is explained in the Author's Notes that follow the last chapter.
Metallica | Metallica's | A Year and a Half in the Life of Metallica | Metallica (album) | Sabera metallica | Metallica Resources | Harrisina metallica | Guitar Hero: Metallica | Eupanacra metallica | De re metallica | Avicularia metallica | Autographa metallica |