Stone Stool by Kartell. Stone is a stool with a simple shape but with a very precious appearance. Made with an essential symmetrical linear shape which is reminiscent of an hourglass, its surface is simply extraordinary: it’s irregular and comprised of a myriad of geometrical facets which reflect the light and create a striking and unique play of colours, much like a diamond. Because of its extreme quality, the Stone stool is offered in the colours of precious stones and precious metals. Stone Stool by Kartell is designed by Marcel Wanders.