sillimanite

from The Collaborative International Dictionary of English v.0.48

Sillimanite \Sil"li*man*ite\, n. [After Benjamin Siliman, an
   American meneralogist.] (Min.)
   Same as {Fibrolite}.
   [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Fibrolite \Fi"bro*lite\ (? or ?), n. [L. fibra a fiber + -lite:
   cf. F. fibrolithe.] (Min.)
   A silicate of alumina, of fibrous or columnar structure. It
   is like andalusite in composition; -- called also
   {sillimanite}, and {bucholzite}.
   [1913 Webster]