Chloritoid forms in Fe-rich metapelites of low to medium metamorphic grade. It has high positive relief relative to quartz and feldspars and is pleochroic in shades of blue-green (A and B, rotated 90 degrees relative to one another).  It commonly forms platy porphyroblasts that are rectangular in random section, and can have an hour glass arrangement of inclusions.  Interference colours typically range to a maximum of pale first order yellow, and simple and lamellar {001}twinning is common (C, D).  Interference colours may be anomlaous due to strong absorption.  Sample is from an uknown location. All views are 5.5 mm across.  A, B, C ppl, D x-nicols.