There is also a small amount of hematite, pyroxene and sericite.
There is some sericite present, also magnetite, resulting from the decomposition of the biotite.
A dark compact rock, in which calcite and sericite predominate.
In igneous rock the ore-bearing solutions may have altered the wall rock to a dense mixture of quartz, sericite, and chlorite.
Alunite is a potassium-aluminum sulphate, which differs from sericite in that sulphur takes the place of silicon.
Where sericite is dominant, the alteration is called sericitic alteration.