The rare personal keepsake will hit the auction block at Christie's New York on January 22. The estimate for it is US$40,000-80,000.
Thomas Jefferson married Martha Wayles on New Year's Day in 1772. After the birth of their 6th child, she grew increasingly ill and died on September 6, 1782. Jefferson never remarried.
The front of the key is beautifully engraved with Martha Jefferson's birth and death dates, and the reverse bears a clear case in which the braided lock of hair is visible.
You can view more information about item and details of the other items for auction on this page of the Christie's site.