Read any geology textbook and it will tell you that winds only routinely transport sediment grains that are smaller than 2 millimeters in diameter. Thus, sand, silt and clay are all regularly moved around by wind but gravel, cobbles and boulders only get picked up by occasional fierce storms.
These rules have left geologists working in the Chilean desert perplexed by the discovery over the years of hundreds of mounds containing tens of thousands large crystal shards of the mineral gypsum. Many of the crystals are over 20 centimeters in length and clearly did not grow in the dry environment where they are being found. How the crystals got where they are has been a long standing mystery but now a new study is revealing the story of how they got there... tiny tornadoes that routinely pass through the area. You can read more in The Economist article that I wrote on this here. Alternatively, if you would like to hear me describe the research on The Economist's science podcast, you can do here.