Aquamarine is a blue or blue-green variety of beryl, a mineral of beryllium aluminum cyclosilicate. The name "aquamarine" is derived from the Latin word "aqua marina," meaning "water of the sea." It has been treasured by various cultures for its beauty and perceived metaphysical properties. The ancient Romans believed it had the power to calm waves and ensure safe sea voyages. In medieval times, aquamarine was thought to enhance the happiness of marriages and provide courage to soldiers.