'Microcrystalline' definitions:

Definition of 'microcrystalline'

(from WordNet)
adjective
Containing crystals that are visible only under a microscope

Definition of 'Microcrystalline'

From: GCIDE
  • Microcrystalline \Mi`cro*crys"tal*line\, a. [Micro- + crystalline.] (Crystallog.) Crystalline on a fine, or microscopic, scale; consisting of fine crystals; as, the ground mass of certain porphyrics is microcrystalline. [1913 Webster]