What is Narsarsukite?
Narsarsukite is a rare yellow-brown sodium titanium silicate from unusual alkaline rocks and pegmatites.
Mineralogy and crystal structure
Reference formula: Na2TiOSi4O10. Narsarsukite is a tetragonal titanium silicate whose colour and density reflect titanium and iron chemistry. Its unusual framework is best understood with the alkaline host rock and associated zircon, aegirine or feldspar minerals. Narsarsukite is classified with silicates and has a tetragonal crystal system. Typical hardness is 5.5–6 on the Mohs scale and specific gravity is approximately 3.4–3.5.
Colour, lustre and habit
Typical colours include yellow, brown, red-brown, black. The usual prismatic, tabular, granular habit and vitreous, resinous lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Narsarsukite forms in or is associated with alkaline nepheline-syenite complexes, pegmatites and titanium-rich late-stage cavities. Important documented localities include Greenland, Canada, Russia, Norway and the United States.
A yellow titanium silicate from an alkaline complex
Narsarsukite is a collector mineral for unusual igneous chemistry: warm colour and sharp form point to a fluid-rich, titanium-bearing stage of alkaline rock evolution.
Collecting and care
Protect crystals from impact and acidic cleaners; keep locality and host-rock information with the specimen.
