The Gnishik Formation is a geologic formation in Armenia, Azerbaijan and Iran. It preserves fossils dated to the Wordian age of the Permian period. The thin-bedded limestones of the formation reach a thickness of 670 metres (2,200 ft) in the Julfa section of northwestern Iran and 300 metres (980 ft) in the Arpa River valley of Armenia. The sediments were deposited in an open marine setting at the northern edge of the Paleo-Tethys Ocean. The coral was named after the formation.