Aquamarine with Quartz and Calcite from Shigar-Skardu, Pakistan. Aquamarine is a transparent blue or blue-green variety of beryl (beryllium aluminum silicate). The color is due to trace amounts of iron within the crystal structure. Beryl occurs in many colors. Green beryl is termed emerald. The rare, transparent beryl varieties are used as gemstones, while the more common types form the principal ore of the metal beryllium, which is widely used in industrial alloys. The main producer of aquamarine is Brazil, but it is also found in Pakistan and the USA. Specimen dimensions are 4.5 x 3.5 x 3 cm.