This is a ring straight out of China’s Qing Dynasty era. It’s 1.2 centimetres (0.47in.) long, 0.7cm (0.28in.) wide, and happens to have a fully functional abacus on it. That’s right, the Chinese were doing arithmetic on a finger-mounted “smartring” long before the gesture sensitive rings of today.
This ring was in fact too small to use with your fingers, but a needle or other sharp pointed object would take care of that. We like to think of this accessory as a prototypical stylus, long before Steve Jobs was even around to be able to hate them.