And David took the crown of their king from off his head, and found it to weigh a talent of gold, and there were precious stones in it; and it was set upon David's head: and he brought also exceeding much spoil out of the city. David took the crown of their king - off his head - See 2 Samuel 12:30.
Precious stones in it - The Targum says, "And there was set in it a precious stone, worth a talent of gold; this was that magnetic stone that supported the woven gold in the air." What does he mean?