Widmanstätten pattern
Estructura de Widmanstätten
- Date
- 1804 · confidence high
- Place
- Naples, Campania, Italy
- Credited to
- William Thomson (the mineralogist, not the physicist Lord Kelvin)
- Field
- Cosmos & Earth
⚠️ Disputed: the sources disagree.
What was discovered
By treating a fragment of the Krasnoyarsk meteorite with nitric acid in Naples, Thomson revealed a crystalline pattern of kamacite and taenite bands (iron-nickel alloys) that only forms through extremely slow cooling, over hundreds to thousands of degrees per million years, across millions of years in space.
Wikidata credits 'William Thomson' (1760-1806), who had already published this observation in French in the 'Bibliothèque Britannique' in 1804, four years before Alois von Beckh Widmanstätten, director of Vienna's Imperial Porcelain works, observed the same pattern in 1808 -without publishing it- by flame-heating meteorites. Carl von Schreibers named the structure after Widmanstätten, and it stuck, even though real priority belongs to Thomson; the Napoleonic wars and his death in 1806 in Palermo overshadowed his discovery.
What it led to
- The standard cut-polish-etch method for identifying iron meteorites
- Estimates of the cooling rates of meteorite parent bodies