Argor-Heraeus' CEO Robin Kolvenbach holds one kilo bars of silver and gold at the plant of refiner and bar manufacturer Argor-Heraeus in Mendrisio, Switzerland, July 13, 2022. Denis Balibouse | ReutersGold and silver prices plunged Friday, as President Donald Trump's nomination for the next chair of the Federal Reserve, Kevin Warsh, appeared to relieve concerns about the central bank's independence and sent the dollar soaring. Spot silver was down 28% at $83.45 an ounce, trading near its lows of...