Aegirine

Aegirine, also known as Acmite, is a sodium iron silicate mineral commonly formed in the alkali-rich volcanic rock. It was discovered in 1835 in Norway and got its name from Ægir, the Scandinavian god of the sea. Aegirine has been seen as black, dark green, or brown and can be found in Russia, Canada, South Africa, and the U. S. A.

In South Africa, aegirine is often found in alkaline igneous rocks, particularly in areas rich in nepheline syenites and other volcanic formations. Notable occurrences of aegirine can be found in the Umkondo igneous province in northeastern South Africa, where it often forms in association with minerals like nepheline, zircon, and feldspar. While not commonly used as a gemstone, aegirine is of interest to mineral collectors and is sometimes used in research for understanding geological processes.