Biotite is primarily used in geological and environmental studies as a key indicator mineral for understanding metamorphic processes and rock history. Its presence and composition help scientists determine the temperature and pressure conditions during rock formation.

In industrial applications, biotite serves as a source of potassium and is occasionally used in the production of certain ceramics and glass due to its thermal stability and resistance to weathering. While some micas are valued for electrical insulation, biotite's iron content makes it less ideal for this purpose compared to other varieties.

It is also utilized in radiometric dating, particularly potassium-argon and argon-argon methods, to determine the age of rocks and geological events. Additionally, biotite’s layered structure makes it useful in research related to ion exchange and mineral behavior under stress.

In agriculture, ground biotite is incorporated into fertilizers as a slow-release source of potassium and other nutrients, helping to improve soil structure and water retention. It also shows potential in environmental applications, such as wastewater treatment, where its ion-exchange properties aid in adsorbing heavy metals and contaminants.