By Brenton Cordeiro

(Reuters) - A more positive outlook in China and India will help boost diamond sales this year, says De Beers, the world's biggest diamond producer, in a further sign the world economy is on a slow path to recovery.

De Beers forecast moderate growth in jewelry demand in 2013, in a turnaround from a 12 percent decline in rough diamond prices last year, which it said was also in line with polished diamond prices.

De Beers, a unit of global miner Anglo American <AAL.L>, said its sales slid 16 percent last year, but a modest recovery in major jewelry markets during the holiday season helped stabilize prices.

"Despite macroeconomic concerns, demand for diamond jewelry continues to grow in the key markets of the United States, China and Japan," Chief Executive Philippe Mellier said on a conference call.

Trading conditions in other developed markets were likely to be challenging, with stocks of unprocessed diamonds still high, De Beers added.