U.S. polished diamond imports in September rose 12.7 percent year on year to $1.659 billion, with the average price per carat increasing 28.8 percent to $1,661. Meanwhile, polished diamond exports rose 1.5 percent to $1.452 billion, leaving net polished imports at $206 million compared with only $42 million in September 2012.

Rough diamond imports fell 2.9 percent to $34 million, while rough exports were unchanged at $17 million, leaving net imports of $17 million compared with $18 million one year ago. The net diamond account for September, reflecting the difference between net imports and exports, surged 271.7 percent year on year to $223 million.

In October, U.S. polished diamond imports jumped 54.1 percent to $2.221 billion, while the average price per carat improved 6.4 percent to $1,741. Polished exports rose 35.4 percent to $1.517 billion, leaving net imports of $705 million, up 119.6 percent from October 2012.

Rough diamond imports jumped 22.2 percent to $33 million, while rough exports increased 65 percent to $33 million, leaving no measurable net imports compared with imports of $7 million one year earlier. The net diamond account in October rose 114.9 percent to $705 million.

Strong polished diamond import figures for the past two months helped to boost the year to date figure by 17.4 percent year on year at $19.269 billion. Polished diamond exports have risen 15.6 percent to $16.23 billion, leaving net imports up 28.2 percent to $3.041 billion.

Rough diamond imports for the first 10 months of 2013 have fallen 1.7 percent to $397 million and rough exports have declined 5.8 percent to $243 million. However, net rough imports have improved 2.7 percent to $152 million. The net diamond account, reflecting the difference between net imports and exports, rose 26.7 percent year on year to $3.193 billion for the January through October period.