"The diamond sutra" is 15.5cm from the edge, the miniature ivory brush is zou ruirong, zou binglong father and son in December 1983, lasted three months. The miniature carving of the ivory brush is a unique skill created by zou xifu, the second inheritor of zou's pen. It has been inherited till now, representing the great crystallization of the ancient culture of "four treasures of the study room" in China.