Antwerp's jewelers say the $30,000 gift proves partnerships, "like the finest natural diamonds, are formed under pressure."

A lavish gold ring encrusted with diamonds, sapphires, emeralds and rubies has been presented to the U.S. ambassador to Belgium to give to President Donald Trump.

US presidents have considerable discretion to accept gifts from domestic and foreign sources and may determine themselves whether a gift was meant for them personally or the…