Caviar is known for its ample use of precious metals when creating custom editions of high end phones. Its latest creation is a response to the COVID-19 outbreak and touts the antimicrobial properties of silver and gold along with protective symbols from cultures from around the world.
Apple iPhone 11 Pro and iPhone 11 Pro Max units are clad in 925 sterling silver while the symbols themselves are created out of 18K gold. There are four versions right now: Hand of Fatima, St. Nicholas, a blooming lotus and a dragon. All but the Hand of Fatima version seem to be limited editions with only 99 units planned.
These start at $5,300 for a 64GB iPhone 11 Pro and go up (each version has a different cost, based on how much gold is on it).
While silverware has been used for centuries, you may be much better off looking into UV-C based sanitizers if keeping viruses and germs off your phone is your goal.