The Collaborative International Dictionary
Microcrystalline
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.
Wiktionary
microcrystalline
a. Composed of microscopic crystals
WordNet
microcrystalline
adj. containing crystals that are visible only under a microscope
Wikipedia
Microcrystalline
A microcrystalline material is a crystallized substance or rock that contains small crystals visible only through microscopic examination.
Usage examples of "microcrystalline".
Tana and Estrela were working together on rock studies, Estrela chipping the outer surfaces off of rocks and Tana pressing the portable X-ray crystallography unit onto the freshly exposed surface to map the microcrystalline structure.