Polyhedral texture in dunite - Scanning Electron Microscope Image

Click on the image to enlarge.  Sample: Michael Velbel; photo: Dan Snyder

Granular (recrystallized) olivine, fractured dunite fragment, Webster-Addie ultramafic body, Jackson County, western North Carolina. Scanning electron microscope (SEM) image (secondary electron image). Magnification 40x.

Thanks to Dr. Michael Velbel, Michigan State U., for the sample, and thanks to Dr. Velbel and NASA for the SEM time. Thanks also to E. Danielewicz for assistance with the SEM.

Polyhedral texture (mosaic texture) in dunite

Click on image to enlarge.           Photo © Daniel R. Snyder.

Classic polyhedral mosaic in dunite. This texture results from recrystallization in the solid state, and is common in metamorphic rocks composed mainly of one mineral, such as dunite. Grains tend to have fairly straight sides, and many grain boundaries intersect in triple junctions at approximately 120˚ angles. Webster-Addie ultramafic body, Blue Ridge Mountains, Jackson County, western North Carolina. Macrophotograph, XPL. Imaged area 8 mm x 14 mm.