Cryptocrystalline
Pronunciation : Cryp`to*crys"tal*line (-krs"tal-ln)
Part of Speech : a.
Etymology : [Gr. krypto`s hidden + E. crystalline.] (Geol.)
Definition : Defn: Indistinctly crystalline; -- applied to rocks and minerals, whose state of aggregation is so fine that no distinct particles are visible, even under the microscope.
Source : Webster's Unabridged Dictionary, 1913