Alrosa’s sales reached their lowest level of the year in December as a depletion of stock led to less available inventory.

The miner sold $254 million in diamonds during the month, 51% less than a year earlier, the company reported Thursday. The figure represented a 24% drop from November.

Rough revenues fell 49% year on year to $241 million, while sales in the polished division plunged 77% to $12 million. Rough sales encompass the company’s monthly trading sessions for contract clients as well as tenders and auctions of 10.8-carat stones and larger.

Alrosa’s inventory has declined due to continued high demand for diamond jewelry, in addition to a drop in production, management explained.