Description
The mineral aegirine is a sodium iron inosilicate with the chemical formula NaFe3+(Si2O6). It belongs to the pyroxenes. Green, reddish-brown, or black aegirine has a yellowish-gray streak color, a vitreous luster, and distinct cleavage along unknown crystal faces. Its average density is 3.52 and its hardness is 6 to 6.5. The crystal system is monoclinic, and the mineral is not radioactive. The mineral aegirine is named after Aegir, the Teutonic god of the sea. Aegirine is a common pyroxene formed primarily in sodium-rich nepheline syenites. The type localities are Konsberg in Buskerud, Norway, and Magnet Cove, Hot Spring County, Arkansas, USA. The mineral is also found on Russia's Kola Peninsula, in Quebec, Canada, and Utah, and in South Africa and the Democratic Republic of Congo.
