The density of biotite varies depending on its chemical composition and the presence of impurities. However, it generally falls within the range of 2.7 to 3.3 g/cm³.

Here's a breakdown:

* Typical Density: 2.8 - 3.1 g/cm³

* Range: 2.7 - 3.3 g/cm³

Keep in mind that these values are just approximations. The actual density of a specific biotite sample may differ slightly due to factors like:

* Iron Content: Biotite with higher iron content tends to be denser.

* Presence of Other Minerals: Inclusions of other minerals can affect density.

* Crystal Structure: Variations in crystal structure can also impact density.

If you need a precise density value, you should consult a specific geological reference for the particular biotite you are interested in.