One of the world's biggest coins is to go on auction Friday, put on the market by Wolfgang Auer von Welsbach whose financial ruin was exposed by the same crisis that has made big chunks of gold a hot item among Austria's traditionally conservative investors.

von Welsbach, the great-grandson of a 19th-century Austrian industrialist who invented the lighter flint and the gas mantle, founded the investment firm AvW in 1991. On May 4, AvW Group filed for bankruptcy, by which time von Welsbach already had been taken into custody, suspected of fraud and embezzlement.