"The sheer magnitude of the loss in confidence was behind the shock," Pepperstone head of research Chris Weston said, noting the 11 point drop to 70.2 was the largest monthly decline since April 2020.
"Is this consumer read the sign of things to come and economic fragility or one event that will offer traders the opportunity to buy USDs at lower levels?"
Sunday marked 50 years since then-US president Richard Nixon made the wide-reaching decision to end the gold standard, an agreement to exchange dollars for gold at US$35 an ounce.
Gold was worth $1,780/oz on the spot market at the time of writing.
Gold miners gained, with major Newmont finishing 0.84% higher in New York.
Producer Pretium Resources jumped 16.8% in Toronto after reporting better than expected quarterly results.
Elsewhere, Russia-focused Polymetal International rose 1.9% in London on Friday and Australia-based Newcrest Mining was up more than 2% in morning trade today.
