- Coal: Pennsylvania has abundant coal reserves, particularly anthracite and bituminous coal. Anthracite coal, often referred to as "hard coal," is known for its high energy content and low ash content. Bituminous coal, also called "soft coal," is widely used for power generation and industrial purposes.
- Natural gas: Pennsylvania has significant natural gas reserves, primarily located in the Marcellus Shale formation. The Marcellus Shale is a sedimentary rock formation underlying parts of Pennsylvania and several neighboring states. It contains large quantities of natural gas, making Pennsylvania one of the leading producers of natural gas in the United States.
- Oil: While not as abundant as coal and natural gas, Pennsylvania has some oil reserves. Oil production in the state primarily occurs in the northwestern region, particularly in counties like McKean and Warren.
- Minerals: Pennsylvania is known for various mineral resources, including sand, gravel, limestone, and shale. Sand and gravel are essential for construction purposes, while limestone is used in various industries, such as cement production and agriculture. Shale, besides being a source of natural gas, is also used in the production of bricks and tiles.