petrology

Rocks of Art

Under the cross-polar light from an optical microscope, this thin section of a rock almost looks like it could be stained glass. The grains of olivine and pyroxene in this peridotite sample display vibrant birefringence interference colors. Not all minerals have such vivid hues under a microscope, though. A mineral’s birefringence depends on its refractive… Continue reading Rocks of Art

petrology

Art of Geology

As a geologist, not only do you have to be good in math, chemistry, physics, history, and writing, but you also kind of need to be decent at art. These are thin sections of magmatic rocks with my accompanying petrographic sketches. For a relatively small little circle, these guys take a really long time to… Continue reading Art of Geology

petrology

Dunite

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… Continue reading Dunite