Kyanite zone (Sample
is Ky + Bt + Ms + Pl + Qtz.
The rock is a coarse-grained kyanite-biotite
schist. The kyanite here shows its characteristic
high relief, low order interference colours (up to
yellow), cleavage and simple twins. The AFM diagram
at right shows the bulk composition plotting in a
two-phase Ky-Bt field, and suggests that staurolite
might still be stable in more Fe-rich rocks under
the same conditions.
Field of view
is 6 mm wide.