Song Dynasty (960-1279) nephrite jade sui. The jade sui is a jade shape that is carved so that it may be attached by cord to the scabbard for a sword. There is a long element below the place for the cord which would allow the scabbard to tuck into a belt, so that it would not be dislodged by the movement of the warrior. It is a common part of the sword from very ancient times in China.
size: 3-3/4 X 7/8 INCHES