Nuummite "flats" ground pieces collection box with 1.5-1.8 kilos of natural Nuummite from Greenland.

Nuummite is a rare metamorphic rock, consisting 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 and thus give the rock its characteristic play of color. Other common minerals in the rock include pyrite, pyrrhotite and chalcopyrite, which create glittering yellow streaks in polished pieces. In Greenland the rock was formed by two successive metamorphoses of an original igneous rock. The intrusion occurred in the Archean, about 2,800 million years ago, and the metamorphism was dated to 2,700 to 2,500 million years ago. The stone was first discovered in 1810 in Greenland by mineralogist KL Giesecke and scientifically defined by OB Bøggild between 1905 and 1924. True Nuummite is only found in Greenland. Due to its iridescent properties, this rare stone is sought after by gem dealers, collectors and enthusiasts of the esoteric. It is often sold with a tumbled finish.