At first glance, a quiet desert floor seems like the last place you’d expect movement. Yet in certain deserts, gravel-size gypsum crystals mysteriously slide across flat, dry ground, leaving long trails behind them. For years, this strange phenomenon puzzled scientists and sparked stories of magnetic forces and hidden life. The real explanation, however, is just as fascinating—and firmly rooted in science.
The Mystery of Moving Stones
These wandering crystals are most famously found on dry lake beds, such as Racetrack Playa in California’s Death Valley. The surface looks smooth and lifeless, but scattered across it are rocks and gypsum crystals that appear to move on their own. Some leave tracks stretching for meters, even though no human or animal is around to push them.
Not Magic—Nature at Work
The movement isn’t caused by earthquakes or strange forces. Instead, it’s the result of a rare combination of water, ice, wind, and a perfectly flat surface.
After rainfall, a thin layer of water forms over the dry lake bed. When temperatures drop at night, this water freezes into a thin sheet of ice around the crystals. As the sun rises, the ice begins to break apart into large floating panels.
Wind Does the Pushing
Once the ice starts to melt, light winds can push these ice panels across the slick, muddy surface. The ice acts like a sail, gently dragging the gypsum crystals along with it. Because the surface is extremely smooth and slippery, even small amounts of wind are enough to move the stones.
This process is slow and rare, but over time it creates the long trails seen in the desert floor.
Why Gypsum Crystals Move Easily
Gypsum is relatively light compared to other rocks, which makes it easier for ice and wind to move. Its shape also helps it slide rather than sink into the ground. These features make gypsum crystals perfect candidates for this unusual desert journey.
A Reminder of Subtle Forces
The moving gypsum crystals show that nature doesn’t always need dramatic power to create amazing effects. Sometimes, gentle forces working together—ice forming overnight, a breeze in the morning, and a smooth surface—can produce one of the desert’s most mysterious sights.
In the end, what moves gravel-size gypsum crystals around the desert isn’t magic or mystery—it’s the quiet teamwork of wind, water, and ice.
