The Collaborative International Dictionary of English v.0.48:

cronstedtite \cron"stedt*ite\ (kr[o^]n"st[e^]t*[imac]t), n.
   (Min.)
   A mineral consisting principally of silicate of iron, and
   crystallizing in hexagonal prisms with perfect basal
   cleavage; -- so named from the Swedish mineralogist
   Cronstedt.
   [1913 Webster]