Richard Hayes left a $45 million coin on the streets of Manhattan all day Tuesday, but he wasn’t particularly worried about a thief carting it off. The coin—with Queen Elizabeth’s profile pressed onto one side and a mid-hop kangaroo on the other—is beyond the wiles of the average pickpocket. It measures nearly 32 inches in diameter and is almost 5 inches thick. Oh, and it weighs about 2,200 pounds. (That is more than 32,000 troy ounces, for the precious-metals buffs out there.) Hayes is the chief executive of the Perth Mint, one of the world’s largest gold refiners. He flew to the U.S. from Australia with the world’s ... (full story)