Polished diamond exports jumped 30.1% by value in September to $1.64 billion, compared to September 2010, according to data released by the Antwerp World Diamond Centre's Diamond Office (AWDC).

In terms of volume, polished exports fell 9.5% to 731,220 carats.

A factor influencing the September polished exports was the Hong Kong Jewellery & Gem Fair in which some 88 Belgian companies participated, AWDC said.

Polished imports rose 32.4% by value to $1.53 million, but dropped 5.3% by volume to 780,151 carats in September, compared to the same period last year.

Belgian exports of rough diamonds soared 27% to $1.06 billion by value in September. By volume exports of rough fell 34.2% to 5.83 million carats.

Rough September imports rose 61.3% by value to $1.03 billion. By volume, rough imports were up 23.1% to 7.29 million carats compared to the same month last year.