Aquamarine Raw Sterling Silver PendantRaw aquamarine in sterling silverthe crystal's natural form preserved rather than polished away. Aquamarine is the blue to blue green variety of beryl (beryllium aluminum silicate), colored by trace ferrous iron (Fe) in the crystal structure. It grows in hexagonal prisms in granitic pegmatites and hydrothermal veins. The raw form shows the mineral's natural surfacethe flat prism faces and slightly frosted texture that a polished cabochon conceals.