Mica minerals occur in different varieties.
Biotite is a dark coloured mica mineral.
It contains iron and magnesium, which gives it a dark appearance.
Because of its dark black or brownish-black colour, biotite is commonly called:
\[
\text{Black mica}.
\]
Muscovite is commonly known as white mica.
Therefore, biotite should not be confused with white mica.
Thus, the correct answer is:
\[
\text{Black mica}.
\]