** Shares of Chow Tai Fook Jewellery 1929.HK fall 3.7% to HK$13.48, their biggest intraday pct drop since June 19

** Stock on course to snap two straight session of gains, if current momentum holds

** The Hong Kong-based jewellery chain operator said its retail sales value for the three-month quarter ended in June down 1.9% y/y, of which retail sales value in mainland China drops 3.3% y/y but up 7.8% y/y in Hong Kong

** Hang Seng Consumption Index .HSCGSI gains 0.2%, benchmark Hang Seng Index .HSI rises 1.3%

** YTD, stock up 100.3%

(Reporting by Donny Kwok)

((donny.kwok@thomsonreuters.com))