Rock Tumbler Left Running Since 2019 Has Produced the Smoothest Object Known to Science

A rock tumbler accidentally left running for approximately six years in a suburban garage has produced what materials scientists are calling the smoothest macroscopic object ever measured, after homeowner Debra Lapidary rediscovered the device while packing for a move. 'I thought it was the washing machine making noise,' said Lapidary, who set up the tumbler in November 2019 as a holiday gift project and then 'completely forgot it existed.' The tumbler, a Lortone Model 3A, had been operating continuously on a surge-protected power strip behind a shelf of paint cans. The stone inside — originally a rough piece of Lake Superior basalt — has been polished to a surface roughness of 0.2 nanometers, surpassing the mirror finish of the Hubble Space Telescope's primary lens. 'This shouldn't be possible with consumer-grade equipment,' said Dr. Franklin Abrasion of MIT's Surface Science Lab, who examined the stone. 'The grit wore away years ago. At some point, the stone was being polished by its own dissolved minerals in the slurry water. It essentially polished itself into perfection.' The stone, which Lapidary had originally intended to give her nephew as a Christmas present in 2019, is now perfectly spherical, weighs 12 grams, and is so smooth that it cannot be picked up with dry fingers. 'I tried to grab it and it just squirted out of my hand like a wet seed,' said Lapidary. 'It shot across the garage, hit the wall, and rolled back to exactly where it started. My nephew said it was the best Christmas present ever, even though it's six years late.' Several museums have expressed interest. The Smithsonian has offered to display the stone alongside its mineral collection, though curators acknowledge the challenge of exhibiting 'an object that cannot be placed on a surface without immediately sliding off.'