Aquamarine crystals at the Denver Museum of Nature and Science:
Pure beryl (beryllium aluminum cyclosilicate) is a clear mineral, but only slight impurities can give it any of a variety of colors. Aquamarine is a blue or turquoise variety of beryl, the color coming from iron ions in the mineral.
Prospector Steve Brancato discovered these crystals in 2004 at Diane’s Pocket, his mining claim on the slopes of Mount Antero in Colorado. What you see here is only a small part of a huge body of aquamarine crystals (more than 100 in all) that make up North America’s largest aquamarine specimen.