Widmanstatten Pattern
Definition
A criss-cross crystalline structure of kamacite and taenite bands visible in polished iron meteorites after etching; formed by extremely slow cooling over millions of years at rates impossible to replicate on Earth; its presence authenticates an iron meteorite.
- Structure
- Criss-cross kamacite and taenite bands
- Visible after
- Etching a polished cross-section
- Formation
- Extremely slow cooling over millions of years
- Significance
- Authenticates an iron meteorite
Common questions
Why can't a Widmanstatten pattern be produced by a terrestrial process or a fake?+
The pattern requires cooling rates on the order of degrees per million years, achievable only inside a slowly cooling asteroid core, a rate no terrestrial furnace or forging process can replicate, making the pattern a reliable natural authenticator.
What does the absence of a Widmanstatten pattern in a suspected meteorite indicate?+
Its absence does not rule out an extraterrestrial origin outright, since some meteorite classes such as stony or stony-iron types do not show this structure, but for a purported iron meteorite it raises doubt and prompts further compositional testing.
Related terms
- Fluid Inclusion
- A microscopic cavity in a crystal trapped at the time of growth, containing the mineralising fluid or melt; analysed by microthermometry (freezing...
- Isoscape
- A map of isotope ratio variation across a geographic area, derived from systematic sampling of soil, water, plant, or mineral material; used...
- Kimberley Process
- The Kimberley Process Certification Scheme (2003), an international mechanism requiring rough diamonds to be accompanied by a certificate confirming they are not...
- LA-ICP-MS
- Laser ablation inductively coupled plasma mass spectrometry; a technique that fires a laser pulse at a sample surface, vaporises a tiny amount,...
- Lead Isotope Ratio
- The ratios of the radiogenic lead isotopes (206Pb, 207Pb, 208Pb) to stable 204Pb; these ratios reflect the age and uranium-thorium content of...