[Radek]

I am not sure whether killing jester Sarles will help. I tried to pickpocket him after pretending to give him the pure ore once. No success. The ore isn't in his inventory after giving it to him. Therefore, killing should not work, too.
One final note. You must not bring the pure ore to the jester when you plan to keep it. If you have both the alloy and the pure ore in your inventory at the jester, the jester will ignore the alloy and take the pure ore. Therefore:
a} Gain the pure ore.
b) Store the pure ore at a safe place.
c) Catch the alloy and go to Sarles.