What is Kvanefjeldite?
Kvanefjeldite is a rare hydrated sodium calcium manganese silicate from the unusual alkaline rocks of Greenland, valued for its open framework and locality significance.
Mineralogy and crystal structure
Reference formula: Na4(Ca,Mn)Si6O16·2H2O. Kvanefjeldite has an orthorhombic silicate structure with water in the framework environment and variable calcium-manganese occupancy. It is a locality-sensitive mineral whose chemistry should be read with the host rock. Kvanefjeldite is classified with silicates and has a orthorhombic crystal system. Typical hardness is 5–6 on the Mohs scale and specific gravity is approximately 2.8–3.0.
Colour, lustre and habit
Typical colours include colourless, white, pale grey, pink. The usual tabular, prismatic, granular habit and vitreous, pearly lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Kvanefjeldite forms in or is associated with alkaline agpaitic rocks and late-stage cavities in nepheline syenite complexes. Important documented localities include the Ilímaussaq complex in Greenland, Russia and other alkaline complexes.
A rare framework mineral from Greenland's classic complex
Kvanefjeldite appeals to collectors who value locality and structure. A pale crystal from the Ilímaussaq complex can anchor a display about alkaline magmas, rare-element mineralogy and the remarkable diversity of Greenlandic pegmatitic rocks.
Collecting and care
Protect crystals from impact and heat; keep the alkaline-rock matrix and locality label with the specimen.
