PHILADELPHIA (Dec. 5) - A family is suing the U.S. Mint, saying it illegally seized 10 gold coins that are among the rarest and most valuable in the world that the family found among a dead relative's possessions. ...... There were 445,500 minted in 1933, but they were melted down before being released into circulation when President Franklin D. Roosevelt took the country off the gold standard. A handful escaped, however. Two were deliberately set aside and are at the Smithsonian Institution. The Mint has said any others in existence were obtained illegally,