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