Crystallite

Crys″tal‐lite (kr?s″tal–l?t), n. [See Crystal.] (Min.) A minute mineral form like those common in glassy volcanic rocks and some slags, not having a definite crystalline outline and not referable to any mineral species, but marking the first step in the crystallization process. According to their form crystallites are called trichites, belonites, globulites, etc.