What works for gold in practice rarely works in theory.

The last three U.S. interest-rate increases that should, all other things being equal, be bad for the metal have seen prices jump in the months that followed.

Gold is up about 7 percent since the Federal Reserve raised rates on Dec. 14. It jumped 13 percent in the two months following the last increase in December 2015 and 6 percent the previous time way back in June 2006.