A couple in Florida enjoying a plate of steamed clams made an unusual discovery: A rare purple pearl. George and Leslie Brock stopped into Dave's Last Resort & Raw Bar on Friday during a day at the beach. George Brock was about halfway through a dozen clams when he chomped down on something hard - a rare iridescent purple pearl. At least one expert said the find could be worth thousands of dollars (euros). "Few are round and few are a lovely color, so this is rare," Vermont gemologist Antoinette Matlins told The Palm Beach Post for its Monday edition. "I think they have found something precious and lovely and valuable."