TORONTO, Sept 10 (Reuters) - Harry Winston Diamond (HW.TO) recorded a loss in the second quarter, as plunging demand cut the diamond miner and retailer's revenues nearly in half, the Canadian company said on Thursday 10 September.

Harry Winston, which owns high-end jewelry shops and a minority stake in the Diavik diamond mine in Canada's Arctic, lost $24.5 million, or 32 cents per share, in the three months ended July 31. That compared with a year-before profit of $49.9 million, or 81 cents a share.

Quarterly sales fell to $94.8 million from $186.1 million, as weaker prices and volumes of rough diamonds sold cut mining revenues by 56 percent, while the retail segment recorded a 40 percent decrease.

However, the company said rough diamond prices rose from the first quarter and sales climbed near the end of the second quarter, suggesting a shift in momentum.

Harry Winston is part-owned by Kinross Gold (K.TO). The majority owner of Diavik is mining giant Rio Tinto (RIO.L).

The company's shares jumped 9.7 percent to C$8.27 during Thursday (10 September)'s session. The results were released after markets closed.

($1=$1.08 Canadian) (Reporting by Cameron French; editing by Rob Wilson)