SHANGHAI, May 25 (SMM) - On May 25, premiums of Jinchuan nickel were 10,500-10,800 yuan/mt. The average premium stood at 10,650 yuan/mt, down 500 yuan/mt from the previous trading day. NORNICKEL nickel was quoted with premiums of 7,500-7,500 yuan/mt, with an average of 7,500 yuan/mt, flat from a day ago. NORNICKEL nickel premiums rose further on shrinking market supply. SMM presumes that the supply tightness will not be eased until next week. Nickel briquette prices were 167,900-169,400 yuan/mt, an increase of 2,350 yuan/mt from the previous trading day. The nickel briquette transactions were slack as it was still traded at premiums over nickel sulphate.