Black Bian Jade Gua Sha stone with side combs for connective tissues release. Bian stone: This stone hails from a mountain in China, where it was struck by a meteor and, therefore, is thought to have notable, supercharged benefits: Bian stone contains over 40 minerals and trace elements. It produces negative ions, so it also has antioxidant properties. Bian stone tools should be used on skin that has been depleted.