A Philadelphia antiques dealer plans to sue the U.S. Mint to recover rare gold coins worth millions of dollars that the federal government has seized because it says they were illegally obtained, Reuters reported. Ten "Double Eagle" $20 coins minted in 1933 were discovered in September in a Philadelphia antiques and jewelry store and voluntarily handed by its owners, the Langbord family, to the Mint for authentication. In June, the mint confirmed they were the coveted Double Eagles but informed the Langbords that the coins were being sent for safe-keeping to the U.S. Bullion Depository at Fort Knox, Kentucky, because the family had no right to them. The coins have grail-like status for coin collectors. Only about 25 out of 445,500 are known to have survived destruction after the United States abandoned the gold standard in 1933 and ordered them melted down. Two of the coins were given to the Smithsonian Institution in Washington for display. A few more survived, and the 10 recently discovered were obtained in 1937 by Israel Switt, an antiques dealer and ancestor of the Langbord family, in whose store the coins were found. Switt died in the 1980s. --more 2344 Local Time 2044 GMT