Oil prices edged up on Friday on the prospect of OPEC+ continuing output cuts, but the crude benchmarks were headed for the steepest weekly losses in three months on demand uncertainty and easing tensions in the Middle East reducing supply risks.

WTI oil has an American Petroleum Institute gravity of 39.6 degrees, considered “light.” WTI also has a sulfur content of just 0.24%, making it very “sweet.” WTI crude oil is typically the benchmark for U.S. oil prices in the trading world.

After years of skepticism, criticism and trader furore, the world’s most important oil price is working better than ever thanks to an infusion of crude from west Texas.

Gold for June delivery fell $1.40 to $2,309.60 per ounce. Silver for July delivery rose 8 cents to $26.83 per ounce, and July copper fell 7 cents to $4.48 per pound. The dollar fell to 153.10 yen from 157.15 Japanese yen. The euro rose to $1.0730 from $1.0728.

Oil futures declined Wednesday, poised for a third straight session loss after official U.S. data revealed an unexpected weekly rise of more than 7

Oil prices rose on Thursday, rebounding from three days of losses that took prices to their lowest since mid-March. Brent crude futures for July gained 58 cents, or 0.7%, to $84.02 a barrel by 1130 GMT.