Geological reserves refer to the quantities of natural resources, such as minerals, oil, or gas, that are found in the Earth's crust and can be extracted economically. These reserves are identified through geological surveys and assessments, which help determine the amount and quality of the resource available. The classification of geological reserves often includes terms like proven, probable, and possible reserves, indicating the level of certainty regarding their existence and extractability. Understanding geological reserves is crucial for resource management and planning in industries like mining and energy production.