Polished imports to the United States rose 23 percent year on year to $1.64 billion in August 2011, the U.S. International Trade Commission reported. Growth was driven by higher prices, rising 46 percent to $1,534.44 per carat, while the volume of imports fell 16 percent to 1.068 million carats during the month.

Polished exports grew 22 percent to $1.38 billion and net polished imports, representing the excess of imports over exports, increased 25 percent to $258 million.

Rough imports to the U.S. remained flat at $31 million in August while rough exports declined by 26 percent to $14 million. Net rough imports, imports less exports, grew 42 percent to $17 million.

The U.S. net diamond account, representing combined polished and rough imports less total exports, grew 24 percent to $241 million.

During the first eight months of the year, the U.S. polished imports rose 27 percent to $14.99 billion and polished exports grew 35 percent to $12.18 billion. Net polished imports were flat for the period at $2.82 billion.

Rough imports increased 27 percent to $424 million and rough exports rose 62 percent to $291 million. Net rough imports fell 13 percent to $133 million.

The U.S. net diamond account for January through August rose 1 percent to $2.68 billion.