Andalusite is the low pressure aluminosilicate polymorph that occurs in some contact metamorphic rocks and low-pressure regional metamorphic terranes.  It commonly occurs as elongate square or cross-shaped prisms, and has two good prismatic {110} cleavages, visible in A and B.  It is typically colourless but some examples have a pale pink to colourless pleochroism, seen in the sector-zoned crystal in C.  Andalusite grains with trails of inclusions in a cruciform pattern are termed “chiastolite” (A - C).  Andalusite has moderate positive relief relative to quartz, feldspar and muscovite, which is apparent in D, in which the margin of the andalusite grain has been replaced by muscovite + quartz + biotite.  The relief of the grain in A is not obvious due to the surrounding opaque minerals.  Maximum interference colours are usually first order grey to white.  Extinction is parallel to traces of {110} cleavage in elongate sections and parallel to the arms of the chiastolite cross in sections cut perpendicular to the c axis.  Samples from unknown locations.  All views are 5.5 mm across.  A, C and D ppl, B x-nicols.