A small amount of chlorite is commonly present in Tokuwa batholith rocks. Most of the observed chlorite appears to have formed in a postmagmatic environment as a replacement product of biotite.

The pleochroism of chlorite is quite distinct: very pale green to grayish yellow green or pale yellowish green. Chlorite in ilmenite-series rocks is more greenish than that in magnetite-series rocks.

Chlorite compositions show the removal of TiO₂, K₂O, and Na₂O with respect to their biotite precursors. The Mg/(Mg+Fe) ratios of chlorite in ilmenite-series rocks (0.40 to 0.43) are nearly constant and similar to those of the host biotite (0.44±), whereas those of chlorite in magnetite-series rocks (0.64 to 0.65) are clearly higher than those of the host biotite (0.39±).

Chlorite in ilmenite-series rocks is generally lower in SiO₂, TiO₂, and CaO than the chlorite in magnetite-series rocks. This may be explained by the difference in the mineral assemblages of the alteration products (see 2, biotite).