DIOPTASE Meaning of DIOPTASE in English /duy op"tays/ , n.a mineral, hydrous copper silicate, CuSiO 3 ·H 2 O, occurring in emerald-green crystals. [ 1795-1805; di- DI- 3 + Gk optasía view ] Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012