Malachite stalactites that are mined in the Congo are sometimes cut into semi-precious slices which are polished to show off the alternating concentric bands of lighter and darker green. These circular formations, that are called bull's eyes, are the result of malachite forming during dry and wet periods. The deep and varied shades of green, combined with its bright polished luster, make this a stunning display specimen, which even has the drip holes at the center as evidence that it came from a stalactite.