Kosmos Black Sapphire and Marcasite Ring in Sterling SilverAbout This Item A striking statement ring with black sapphires and sparkling marcasite stones in a multi band design inspired by the celestial shapes of the cosmos. Gemstone Information Marcasite items, including jewellery, have been found in ancient Incan tombs. It is thought that the Incas even created marcasite plates and surfaces to be used in worship of sun gods. It has also been said that Native Americans once used marcasite, or pyrite as it is