WASHINGTON — The U.S. penny is not what it appears to be, and some in Congress would like to see it change further, if not disappear entirely. Because of a surge in the price of copper, the U.S. Mint decided 25 years ago to manufacture the coins almost entirely with zinc, save for the coating on which Abraham Lincoln’s profile is engraved. Now, the fate of the penny is up in the air once again. With the price of zinc soaring amid a worldwide commodities boom, it costs the government about 1.7 cents to make each 1-cent coin — a pretty penny considering roughly 8 billion new ones are placed into circulation annually.