De Beers, the world’s largest diamond producer, said it will make a major investment in promoting the stones in the U.S. and China to help boost flagging consumer demand.

De Beers will target the two biggest diamond markets during the year-end holiday season, the Anglo American Plc unit said in a statement Tuesday. The company said it will launch so-called category marketing, where it promotes diamond jewelry in general rather than just its own branded gems.

Challenged by other luxury products such as handbags and iPads, the diamond industry is seeking to ensure their stones continue to appeal to consumers, especially millennials who have not been as exposed as older generations to advertising. The end of De Beers’s monopoly a decade ago led the company to reduce its marketing spending that benefited the entire industry.

“This will help to stimulate downstream demand for polished diamonds and create renewed momentum in the diamond sector at a crucial point in the year,” Philippe Mellier, De Beers’s chief executive officer, said in the statement.

Diamond prices have been under pressure as traders, cutters and polishers struggle to turn a profit amid a credit squeeze and languishing jewelry sales. De Beers has twice cut its 2015 rough-diamond production goal and lowered prices at its current sale in Botswana to help stimulate demand.

De Beers said the campaign will run alongside its “A Diamond is Forever” holiday campaign to promote its Forevermark stones.