Gold rose as high as $US1260 an ounce overnight after US Federal Reserve chair Janet Yellen testified to Congress this week.

"Yellen had to recognise both the underlying strength of the US domestic economy while addressing the potential downside impact of heightened financial market volatility," ANZ Research said.

"That's a tough balancing act to strike when markets are edgy."

According to Bloomberg, yesterday was gold's best day in seven years, putting it on the verge of a bull market.

Nickel appears to be in freefall, slumping 8.9% over the week to $7561.50 per tonne, a fresh 13-year low.

Copper, by comparison, dropped by less than 4% to close at $4454.25/t.

Oil slipped back below $27 a barrel.