Briquettes are a solid fuel prepared from coal dust and fines (i. e., finely crushed or powdered coal) by adding a binder and holding it under pressure.
The binder is commonly pitch or coal tar, but other substances and materials are also used. A briquette made with a pitch binder has the highest caloric value, exceeding that of any coal. The ash content is generally less than that of coal. Briquettes have been made from lignite coal dust and fines without a binder (only pressure being used).