Diaspore
Diaspore , noun
[From Greek {not transcribed} a scattering; dia` through, asunder + {not transcribed} to sow, scatter like seed: compare French diaspore.]
(Mineralogy) 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.