Description
Nuummite is a rare metamorphic rock composed of the amphibole minerals gedrite and anthophyllite. It is named after the area around Nuuk in Greenland, where it is found. Nuummite is predominantly black and opaque. It contains two amphiboles, gedrite and anthophyllite, which form exsolution lamellae, giving the rock its characteristic iridescence. Other common minerals in the rock are pyrite, pyrrhotite, and chalcopyrite, which create shimmering yellow streaks in polished pieces. In Greenland, the rock formed through two successive metamorphisms of an original igneous rock. The intrusion occurred in the Archean, approximately 2800 million years ago, and the metamorphism has been dated to between 2700 and 2500 million years ago. The stone was first discovered in 1810 in Greenland by mineralogist K.L. Giesecke and scientifically defined by O.B. Bøggild between 1905 and 1924. Genuine nuummite is found only in Greenland. Because of its iridescent properties, this rare stone is sought after by gemstone dealers, collectors, and enthusiasts of the esoteric. It is often sold with a tumbled finish.
