If the amped-up prices of gold and ­silver weren’t giving jewelers big-enough headaches, now they must contend with more-expensive diamonds.De Beers on Feb. 11 reported its rough prices rose 27 percent throughout 2010, mostly due to strong polished sales in China and India, where gem demand has soared more than 20 percent. In February, India’s Gem & Jewellery Export Promotion Council estimated that rough prices in January were 27.2 percent higher than the previous year.And it looks like diamonds will only get pricier: Louise Prior, spokeswoman for the DTC, De Beers’ sales and ­marketing arm, says the company “had mid to high single-digit increases on a number of our [sight] boxes” in February. She declined to say which rough diamonds would be increasing in value.According to dealers, the jumps have been felt across the board.“Basically, everything is going up,” says J