The Kaliningrad Oblast contains the world's largest amber deposits.

An excerpt from the article 24 facts about Kaliningrad

They probably cover over 90% of the world's resources of this raw material. Most amber is mined in the area of the Yantarny estate, where it is often processed.

There are also small deposits of high-quality crude oil (with low sulfur content) - production is at the level of 1 million tons, with the possibility of increasing it to 1.5-2.0 million tons per year.