Cordierite, Orthopyroxene and Biotite from near Kazabazua, Quebec
The four photos above are of a spectacular
rock from near Kazabazua, Quebec. It contains primarily cordierite
and orthopyroxene with lesser amounts of
biotite. The cordierite is twinned
(and in XP looks a lot like plagioclase)
and contains pleochoric halos around
zircon inclusions. The halos appear as "burn" marks
in PP light. The orthopyroxene is blocky
and fractured, shows high relief (PP),
and has first order interference
colors (XP). It is pleochroic, with
color ranging from light pink to light green. Biotite
is also pleochroic and here exists as
flakes in various shades of brown (PP) and has upper 2nd order
interference colors (XP).
Cordierite, Biotite and Quartz from near Ft. Coulonge, Quebec
Imperfectly twinned cordierite makes up most of this view (large grain at center of photo). A number of flakes of biotite and a few grains of quartz surround the cordierite. The small high-relief material in the center of the cordierite grain are needles of sillimanite.
The field of view is about 2.5 mm across.
Cordierite, Garnet and Biotite
This sample contains large twinned cordierite (left side) and a highly fracture garnet with some quartz inclusions (right side). Minor biotite and quartz are also present. The cordierite interference colors and twins, visible in the XP view, make this cordierite appear similar to some plagioclase. The garnet is isotropic and so is black in the XP view.
These photos are from the same thin section
as the preceding ones.