Diamond Outlook 2016: Summer to Bring Higher Prices? …Marcus also identified some positivity, stating that the year’s rough diamond price drop didn’t extend to fancy colored diamonds. “Overall in fancy colored diamonds prices went up by 5 to 6 percent on average,” he said. “Some colors, such as pure blue and pink, have increased even more. Rarity and high demand by affluent people have caused prices to increase, similar to art.”