Purple sand is a rare geological phenomenon primarily caused by the erosion of almandine-pyrope garnet or manganese deposits in nearby cliffs. The most famous example is Pfeiffer Beach in Big Sur, California, where the surrounding mountains are rich in these minerals. When heavy rains or strong waves wash down the manganese garnet from the hillsides, the particles accumulate on the shore. Because garnet is significantly denser than the "regular" tan quartz sand, the waves act as a natural filter; they wash away the lighter quartz while leaving the heavier purple crystals concentrated in striking streaks across the beach. In 2026, geologists also point to other purple beaches in the Canadian Shield and Massachusetts, where glacial movement thousands of years ago deposited these mineral-rich sediments. The color is most vibrant immediately after a winter storm or rainfall, which "freshens" the supply of minerals on the beach surface. Depending on the specific mineral mix, the hue can range from a light lavender to a deep, royal magenta.