Polychroism Obviously, a blue-green to blue. 7.5 hardness, density 2.68-2.80 grams / cubic centimeter.是什么意思_Polychroism Obviously, a blue-green to blue. 7.5 hardness, density 2.68-2.80 grams / cubic centimeter.在线翻译_英语_读音_用法_例句