EUCLASE Meaning of EUCLASE in English /yooh"klays, -klayz/ , n.a rare green or blue mineral, beryllium aluminum silicate, BeAlSiO 4 (OH), occurring in prismatic crystals. [ 1795-1805; ] Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012