Thin section of dunite under XPL.
Dunite is a type of peridotite that contains over 90% olivine and may either be found in ophiolitic complexes or xenoliths in basalt lavas.
Note the ‘bubble’ texture of the vibrant birefringent olivine grains at the top and bottom of the image, and the serpentine (gray and white) and talc (high pastel birefringence) running through the center of the image.
Image by author, specimen from Lawrence University
Emily Zawacki, Ph.D. 