Other industrial metals prices were also in the red, pressured by a firmer dollar and uncertainty about global economic growth and demand, especially in top metals consumer China.
Prices of nickel, used mostly in making stainless steel, soared to their highest since June 2018 on Thursday after rising 20% in the previous two weeks.
Three-month nickel on the London Metal Exchange failed to trade in official open outcry activity and was bid down 2.7% at $14,350 a tonne.
"We're more in a stage of profit-taking rather than aggressive shorting the market. There's a lot of concern because we have a large buyer with deep pockets, and standing in the way of that can be challenging," said Citi analyst Oliver Nugent in London.
He was referring to a Reuters report that Chinese firm Tsingshan Holding Group has been buying large quantities of nickel on the LME to supplement its own output.
Nugent said Citi forecast that prices would ease back to $13,500 a tonne in the fourth quarter based on supply/demand fundamentals and marginal prices, but in the meantime prices could be volatile.
"Flows can dictate the direction of the market as long as that position is funded. The question is do the flows come back with full force or are things allowed to settle?"
* NICKEL INVENTORIES: LME nickel inventories carved out a fresh low since January 2013, data showed, having shed about 30% so far this year.
* FERROUS COMPLEX: Steelmaking ingredients nickel and zinc were weighed down by losses in the Chinese ferrous complex, where benchmark Dalian iron ore futures fell 1.6%.
* ZINC TIME SPREADS: The discount of cash LME zinc to the three month contract sunk to $11.50 a tonne by Friday's close, the biggest discount since September last year, indicating healthier near-term supplies.
This compares to premiums of $12 a week ago and $161 in late May, when buyers were worried about potential shortages.
* ZINC PRICE: CTA (Commodity Trade Advisor) funds, often driven by computer algorithms, were selling zinc on Monday morning, Al Munro at broker Marex Spectron said in a note. LME zinc lost 0.8% to trade at $2,406 a tonne in official rings.
* DOLLAR: The dollar gained against the euro on safe-haven demand, making commodities priced in the US currency more expensive for buyers using other currencies.
* ALUMINIUM OUTPUT: Global primary aluminium output fell to 5.246 million tonnes in June from revised 5.406 million tonnes in May, data showed.
* PRICES: Benchmark LME copper fell 0.6% to trade at$6,030 a tonne in official activity, aluminium traded 0.7% lower at $1,835, lead was bid down 2.2% at $2,006 and tin shed 0.6% to $17,730.