Aegirine is a mineral. It is a member of the clinopyroxene group of inosilicate minerals. Acmite is a fibrous green-colored variety of aegirine, with the name also used as a synonym. It was first described in 1821, in Kongsberg, Norway.

Etymology

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

thumb|left|[[Syenite with aegirine and acmite from Magnet Cove, Arkansas, US]]

Aegirine is the sodium endmember of the aegirine–augite series.

It has the chemical formula NaFeSi<sub>2</sub>O<sub>6</sub>, in which the iron is present as the ion Fe<sup>3+</sup>. 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. 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

  • List of minerals

References

  • Mineral Galleries