Photo taken on Nov. 13, 2018 shows the processing of kimberlite ore in Republic of Sakha (Yakutia), Russia. Alrosa, the world's leading diamond miner, has operations in Republic of Sakha (Yakutia) and Arkhangelsk region, running 11 kimberlite pipes and 16 alluvial deposits in the harsh climate of the Russian Far North. (Xinhua/Evgeny Sinitsyn)

A man checks a piece of diamond in an Alrosa facility in Mirnyi, Republic of Sakha (Yakutia), Russia, on Nov. 12, 2018. (Xinhua/Bai Xueqi)

People take photos of polished diamonds in an Alrosa facility in Moscow, Russia, on Nov. 14, 2018. (Xinhua/Bai Xueqi)

Photo taken on Nov. 12, 2018 shows diamonds getting sorted in an Alrosa facility in Mirnyi, Republic of Sakha (Yakutia), Russia. (Xinhua/Bai Xueqi)

A mining excavator loads a truck in an open pit diamond mine in Republic of Sakha (Yakutia), Russia, on Nov. 13, 2018. (Xinhua/Bai Xueqi)

Photo taken on Nov. 13, 2018 shows the processing of kimberlite ore in Republic of Sakha (Yakutia), Russia.(Xinhua/Evgeny Sinitsyn)

Aerial photo taken on Nov. 13, 2018 shows an open pit diamond mine in Republic of Sakha (Yakutia), Russia.(Xinhua/Bai Xueqi)

A tilt-shifted photo shows sorted diamonds in an Alrosa facility in Mirnyi, Republic of Sakha (Yakutia), Russia, on Nov. 12, 2018. (Xinhua/Evgeny Sinitsyn)

Workers polish diamonds in an Alrosa facility in Moscow, Russia, on Nov. 14, 2018. (Xinhua/Bai Xueqi)

A topographic engineer examines an open pit diamond mine in Republic of Sakha (Yakutia), Russia, on Nov. 13, 2018. (Xinhua/Evgeny Sinitsyn)