GABORONE, Feb. 21 (Xinhua) -- Global diamond company De Beers Group says its total revenues increased by 4 percent to 6.1 billion U.S. dollars in 2018, driven by improved consumer demand for diamond jewellery in major markets including the United States and China.

Paul Rowley, De Beers Group executive vice president for diamond trading made this revelation on Thursday when presenting the group's preliminary financial results for 2018 in Gaborone, Botswana's capital city.

The increase in revenues came with a 3 percent increase in rough diamond sales in 2018, totaling 5.4 billion U.S. dollars. Rough diamond production also increased by 6 percent to 35.3 million carats in 2018, according to the preliminary financial results.

De Beers Group is an international corporation that specializes in diamond exploration, diamond mining, diamond retail and industrial diamond manufacturing sectors and its mining operations take place in countries such as Botswana, Namibia, South Africa and Canada.

According to Rowley, preliminary data for 2018 indicates an improvement in global consumer demand for diamond jewellery.

"De Beers Jewellers opened new stores in Hong Kong and Xi'an, China. And the growth in revenue has been phenomenal because a number of middle class Chinese nationals have the capacity to buy diamond jewellery," he said.