cryptocrystalline Meaning, Definition & Usage

Cryp`to*crys"tal*line adjective
Etymology
Gr. krypto`s hidden + E. crystalline.
Definitions
  1. (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.

Webster 1913