The tumbler has an all-over 3D faceted design that resembles light-reflecting gemstones, and placards on each side. The debossed Starbucks logo on a blurred circle appears on one side. Meanwhile ...

If you’re reading Hackaday, there’s a good chance you had a rock tumbler in your younger days. Hell, we’d put odds on a few of you having one rumbling away in the background as you read this.