Biotite is primarily used in geological and environmental studies as a key indicator mineral in understanding metamorphic and igneous rock formation. Due to its layered silicate structure and high content of potassium and magnesium, it serves as a valuable material in radiometric dating, especially in potassium-argon and argon-argon methods, helping determine the age of rocks and geological events.

In industrial applications, biotite is occasionally used in the production of ceramics and glass as a fluxing agent, lowering melting temperatures and improving product consistency. It is also utilized in some cosmetic and paint formulations as a natural pearlescent pigment due to its reflective properties.

In soil science, weathered biotite contributes to the availability of potassium for plant growth, making it relevant in agricultural contexts. Additionally, its ion-exchange capacity is explored in environmental remediation for capturing heavy metals from contaminated water.