1 Chronicles 20:2-3

2And David took the crown of their king from his head. He found that it weighed a talent of gold, and in it was a precious stone. And it was placed on David's head. And he brought out the spoil of the city, a very great amount.

3And he brought out the people who were in it and set them to labor with saws and iron picks and axes. And thus David did to all the cities of the Ammonites. Then David and all the people returned to Jerusalem.