Chinese jade "bi" pendant, symbol of "Heaven", also sometimes called "donut" pendants.  The photo shows several, they are genuine natural Chinese jade and all are slightly different.   Size is approximately 25mm.  Both sides smooth and polished.  This kind of pendant is auspicious to wear all the time, for happiness, health, good fortune, and especially auspicious to wear during holidays.

These are traditionally worn with "dragon whiskers" silk adjustable cord, view the selection here

Made by Ying Yu Jade carver in China, who purchases the jade from the mines and carved to high standards.