Polished diamond prices softened in September, with trading at the Hong Kong Jewellery & Gem Fair reflecting undcertainty over weak currencies and US-China trade tensions.The RapNet Diamond Index (RAPI™) for 1-carat diamonds slid 0.3% during the month and 1.1% in the third quarter. The index is up 2.2% since January 1, following firm US and Chinese demand in the first half.The diamond market was quiet throughout the third quarter as dealers closed for summer vacations and Jewish holidays.

The Hong Kong show didn’t provide its usual boost after the seasonal slowdown, though there was steady demand for 1-carat, D-H, VS-SI goods and 0.30- to 0.50-carat, D-J SIs. There was relative weakness in 0.30-carat, D-H, IF-VVS diamonds — which are popular in the Chinese market — reversing the upward trend of the first half.

Trading was cautious after the yuan dropped 3.8% in the third quarter to CNY 6.87/$1 on October 1, while the Indian rupee fell 5.9% to INR 72.5/$1 in the same period, creating restraint among buyers from those countries. The decline raises operating costs for companies supplying their local markets, since they buy diamonds in US dollars and sell in domestic currencies. Chinese jewelers were also concerned that new US import tariffs would slow economic growth and impact consumer confidence during the October 1 National Day and the Chinese New Year, which begins February 5.

Dealers are now focused on the US ahead of the fourth-quarter holiday season, with Indian manufacturers keeping production relatively low before factories close for the November 7 Diwali break. Expectations are rising for holiday demand; the hope is that improving jewelry sales will support polished prices in the final months of the year.