The milky, smooth texture of beach glass evokes a history of turbulent transport, rough edges abraded away to produce curves. The same smooth features can be seen in river rocks and dune sands.

Combining mathematical models with laboratory experiments and field measurements from a river, an ocean, and a dune field, a team led by University of Pennsylvania geophysicist Douglas J. Jerolmack has found that the same general processes guide the rounding of those diverse particle types. They reported their findings in the journal Science Advances.

“We show that wind-blown sand, river pebbles, and wave-worked pebbles all round in the same way by colliding,” Jerolmack says. “And, more important, we show how nature selects for the conditions that lead to this universal behavior.”

See https://penntoday.upenn.edu/news/river-ocean-or-wind-rocks-round-same-way for more.