What is Wadsleyite?
Wadsleyite is a high-pressure magnesium silicate polymorph of olivine and an important mineralogical model for the Earth's mantle transition zone.
Mineralogy and structure
Reference formula: Mg2SiO4. Wadsleyite has the olivine composition Mg2SiO4 but an orthorhombic high-pressure structure. COD 9000817 is used as an exact nominal wadsleyite reference; natural grains may contain water and iron. Wadsleyite is classified with silicates and has orthorhombic crystal symmetry. Typical hardness is 6–7 on the Mohs scale and specific gravity is approximately 3.8–4.0.
Colour, lustre and habit
Typical colours include colourless, white, pale green, yellowish. The usual granular, massive, microscopic habit and vitreous, pearly lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Wadsleyite forms in or is associated with meteorite shock events and deep-mantle pressure-temperature conditions; it is rarely a conventional hand specimen. Important documented localities include meteorites, shock experiments and high-pressure laboratory or mantle-derived research samples.
A deep-Earth polymorph of olivine
Wadsleyite turns a familiar olivine formula into a mantle story: pressure changes the atomic arrangement and may allow significant hydrogen storage in the transition zone.
Collecting and care
This is a research mineral rather than a casual ornamental stone. Protect grains from contamination and record whether the material is natural, shocked or synthetic.
