While wearing this ring you can offer a precious metal or gem in exchange for temporary resistance. For every 25 gp, or equivalent value in gems offered, the ring receives a charge granting resistance in correspondence to the precious metal or gem that was offered. The ring expends a charge when you receive damage it granted resistance to. You can only have one type of resistance at a time.  The precious metal or gem is consumed by the ring immediately after offering it. After 8 hours, any remaining charges are depleted, regardless if the damage type was taken. Once all charges are expended, a new precious metal or gem can be offered.