Federal Reserve Chairman Alan Greenspan has had to endure some good-natured ribbing about his personal investment in the diamond market: the engagement ring he bought his fiancee.

Greenspan, 70, and NBC News correspondent Andrea Mitchell, 50, plan to marry April 6.At a hearing Tuesday in Washington, D.C., Senate Budget Committee Chairman Pete Domenici, R-N.M., noted that Greenspan had "recently invested in diamonds and you will probably soon be investing in gold."

The ranking Democrat, Sen. Frank Lautenberg of New Jersey, suggested that to avoid a gold rush - caused presumably by investors seeking to read financial advice into Greenspan's purchase - the central banker might consider platinum for the wedding ring.