Symplectites in NWA 5784 diogenite

The wavy black forms signal a symplectitic texture. Symplectites appear in metals, minerals and other materials. They are intergrowths of two or more constituents and appear in a variety of configurations. They may be considered a disequilibrium textural feature. The different phases may form from: a single phase that becomes unstable from a pressure or temperature change (e.g. exsolution); a reaction between adjacent materials; the introduction of a reactive fluid.

In this dunitic diogenite the dark mineral is very likely chromite, according to a researcher who has worked on similar meteorites.

Cross-polarized light. Field of view is 0.4mm wide.

Cross-polarized light. Field of view is 3mm wide.

Plane-polarized light. Field of view is 3mm wide.

Incident light. Field of view is 3mm wide.

Cross-polarized light.

Cross-polarized light.

Cross-polarized light.

About the Author

John Kashuba
John is a natural history enthusiast living in Oregon.
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