Chiastolite

n. [ Gr. chiasto`s marked with a χ + -lite. See Chiasm. So called from the resemblance of the cross cuts of its crystals to the Greek letter χ. ] (Min.) A variety of andalusite; -- called also macle. The tessellated appearance of a cross section is due to the symmetrical arrangement of impurities in the crystal. [ 1913 Webster ]