What is Wadalite?
Wadalite is a rare calcium aluminium silicate chloride, usually found as pale granular material in high-temperature skarns and contact zones.
Mineralogy and structure
Reference formula: Ca6Al5Si2O16Cl3. Wadalite is cubic and natural crystals commonly contain Fe, Mg and vacancies. COD 9011374 is used as a labelled representative natural model rather than an idealised analysis of every specimen. Wadalite is classified with silicates and has cubic crystal symmetry. Typical hardness is 5–6 on the Mohs scale and specific gravity is approximately 2.9–3.1.
Colour, lustre and habit
Typical colours include colourless, white, pale yellow, brown, greenish. The usual cubic, granular, massive habit and vitreous, resinous, dull lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Wadalite forms in or is associated with high-temperature skarns, contact-metamorphic rocks and chlorine-rich calcium-aluminium assemblages. Important documented localities include Japan, Italy, Russia, Austria, Germany and other contact-metamorphic localities.
A rare cubic silicate from a skarn
Wadalite is a specialist collector mineral whose value comes from rarity, crystal chemistry and geological context. Pale cubic grains are most useful when the locality and associated skarn minerals are documented.
Collecting and care
Protect from impact and acids; clean gently with a soft brush and retain the skarn association and analytical information.
