ScienceShot: Shaving a Diamond

How do you cut the hardest thing on Earth? Jewelers know it can be done; they've been cutting diamonds for centuries with other diamonds. Materials scientists just didn't know why this worked. Now they do, thanks to a new computer simulation of two diamonds rubbing against each other under high pressure. According to the model, published online yesterday in Nature Materials, carbon atoms on one diamond (left arrow) latch onto carbon atoms poking out from the other diamond (curved arrow) and briefly pull them along, breaking and reforming atomic bonds as they go. This creates an amorphous surface with liquid-like properties, which allows the diamond to be cut. The findings could lead to a new generation of amorphous diamond coatings on objects such as car pistons, which could rub against each other at high speeds without wearing down and with minimal lubrication.

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