'Cryptocrystalline' definitions:

Definition of 'Cryptocrystalline'

From: GCIDE

Cryptocrystalline \Cryp`to*crys"tal*line\ (-kr?s"tal-l?n), a. [Gr. krypto`s hidden + E. crystalline.] (Geol.) Indistinctly crystalline; -- applied to rocks and minerals, whose state of aggregation is so fine that no distinct particles are visible, even under the microscope. [1913 Webster]