Scrimshawed whale tooth

Summary: 
Antique scrimshawed whale tooth with whaling ship Challenge and portrait of Captain Robert Waterman
Description: 

4.5" scrimshawed whale tooth.  ANTIQUE.  On front side, etching of clipper ship at full sail with the words "Challenge New York to California" inside of banner near the bottom.  On the underside of tooth, the portrait of a man and the words "Captain Robert Waterman".  Slight chip on bottom of tooth.  Obtained by donor from New Jersey.  Artist unknown.