Formula: Na₂KLiFe²⁺₂Ti₂Si₈O₂₄

Species: Silicates – (Phillosilicates)

Colour: Black

Lustre: Vitreous

Hardness: 5 – 6

Specific Gravity: 3.19 – 3.23

Crystal System: Monoclinic

Member of: Neptunite Group

Name: For Neptune, Roman god of the sea, for close association at type locality with aegirine (named after Aegir, a Scandinavian sea god).

Type Locality: Narssârssuk pegmatite, Narsaarsuk Plateau, Igaliku, Kujalleq – Greenland

The Fe(II) analogue of manganoneptunite.