lagoniteMin.|ˈlægənaɪt| [f.It.lagone lagoon n.2; named by Huot, 1841: see -ite.] A hydrous borate of iron from the Tuscan lagoons. 1850Dana Min. 446 Lagonite. An earthy mineral of an ochreous yellow color.1868Ibid. (ed. 5) 600 Lagonite..occurs as an incrustation.