Inner diameter 16.5mm, unisex. The glossy, deep green is beautiful, isn't it? (o^^o) Although not every bead has one, the eye patterns are lovely♪ For those who want to protect themselves from disasters and misfortune. For those who are prone to stress, and those seeking inner peace. For those in dangerous professions. As a charm for children. For those who want to improve their luck. Power stones are not scientifically proven. Please think of them like a Shinto shrine amulet. Notes: Malachite is fragile and sensitive to water, acids, and heat. It needs to be handled gently, avoiding impacts and high temperatures/humidity. #NaturalStone #Malachite #PowerStone