Aegirine

The name aegirine is derived from Ægir, a Norse mythological figure (god of the sea), as the mineral was first described from Norway. ==Chemistry and description==

with aegirine and acmite from Magnet Cove, Arkansas, US Aegirine is the sodium endmember of the aegirine–augite series. It has the chemical formula NaFeSi2O6, in which the iron is present as the ion Fe3+. In the aegirine–augite series, the sodium is variably replaced by calcium with iron(II) and magnesium replacing the iron(III) to balance the charge. Aluminum also substitutes for the iron(III). Acmite is a fibrous green-colored variety. Aegirine occurs as dark green monoclinic prismatic crystals. It has a glassy luster and perfect cleavage, "in two directions at near 90 degree angles". It is described on Mindat.org as "slightly resinous", with its colour "dark green to greenish black, reddish brown, [or] black" Its Mohs hardness is 6 and its specific gravity is between 3.5 and 3.6. Associated minerals include augite, nepheline, andradite, baryte, quartz, spessartine, riebeckite, biotite, sodalite, and albite. ==Occurrence==

The acmite variety was first described in 1821, at Kongsberg, Norway, and the aegirine variety in 1835 for an occurrence in Rundemyr, Øvre Eiker, Buskerud, Norway. Aegirine also occurs in the syenite at the Bowral quarries in New South Wales, Australia, as described in a 1906 paper by geologist and later Antarctic explorer Douglas Mawson. ==Uses==

Aegirine is sometimes used as a gemstone. ==See also==