Luxury jeweler and watchmaker Harry Winston Diamond Corp said production at its Diavik mine in Canada's Northwest Territories was up about 19 percent in the first quarter on improved grades.

Photo: Harry Winston Diamond Corporation

The Diavik mine, which is operated by Rio Tinto Plc , produced 1.60 million carats of diamonds in the quarter.

Average grade increased to 3.0 carats per tonne from 2.8 carats per tonne, a year ago, said Harry Winston, which gets 40 percent of output at Diavik.

Harry Winston has right of first refusal for Rio Tinto's 60 percent interest in their joint Diavik diamond mine.

The company continues to see production of about 8.3 million carats from the mine this year. The Diavik mine produced 6.7 million carats in calendar 2011.

Shares of Toronto-based Harry Winston, which has a market value of C$1.18 billion, closed at C$13.95 on Monday on the Toronto Stock Exchange.