Colorful Volcanic Ash
An ash sample from Mexico’s Popocatépetl volcano viewed under polarized light shows that volcanic ash is not as gray as it appears to the naked eye. Image captured with an Olympus DP72 camera through an Olympus BX52 microscope with 10× magnification and polarized light technique.
—Baruc Zago Mazzocco, Instituto Nacional de Astrofisíca Óptica y Electrónica, Tonantzintla, San Andres Cholula, Puebla, Mexico