The Collaborative International Dictionary of English v.0.48:

Diaspore \Di"a*spore\, n. [From Gr. ? a scattering; dia`
   through, asunder + ? to sow, scatter like seed: cf. F.
   diaspore.] (Min.)
   A hydrate of alumina, often occurring in white lamellar
   masses with brilliant pearly luster; -- so named on account
   of its decrepitating when heated before the blowpipe.
   [1913 Webster]