The price of 1 ct. polished diamonds rose 19 percent in 2011, according to the RapNet Diamond Price Index.

The gains were particularly pronounced in the first half of the year, spurred by strong demand in the Far East and India, the company said. However, some of the gains were erased in the second half, as concerns grew about the international economy and political instability, and liquidity tightened in India.

While the Index found that the price of 1 ct. polished diamonds rose 19 percent over the year, the price of 0.30 ct. stones fell 1 percent. In addition, the price of 0.50 ct. stones increased 20 percent, the price of 2 ct. stones jumped 15 percent, and 3-caraters rose 18 percent.

“Diamonds did extremely well during the first half of 2011 but declined sharply during the second half,” said Martin Rapaport, chairman of the Rapaport Group, in a statement. “Prices have stabilized over the new year but uncertainty prevails due to adverse economic conditions.”

He added that  “U.S. demand held up well over the holidays and will likely remain stable during 2012.”

The RapNet Diamond Index is based on the best asking price for the top 25 quality 1 ct. round diamonds offered for sale on the RapNet computer network.

JCK