microcrystalline

Microcrystalline describes materials in which the constituent crystals are very small, typically on the micrometer or nanometer scale, resulting in a fine-grained or intergrown crystalline texture. The term is used across geology, mineralogy, materials science, and industry to indicate crystallinity that cannot be resolved as large individual crystals.

In geology and mineralogy, microcrystalline textures are common in rocks formed or compacted from fine-grained materials. Micrite refers to carbonate mud composed of microcrystalline calcite grains too small to distinguish individually. Microcrystalline quartz, sometimes called cryptocrystalline quartz, forms in rocks such as chert and flint, where the quartz crystals are too small to resolve with ordinary microscopy.

In materials and consumer products, microcrystalline cellulose (MCC) is a refined derivative of cellulose used as a filler, binder, and disintegrant in pharmaceuticals and as a food additive. Microcrystalline wax is a petroleum-derived wax with a fine crystalline structure used in cosmetics, polishes, and coatings.

In carbon materials, microcrystalline diamond (MCD) refers to diamond consisting of intergrown microcrystals, produced by methods such as chemical vapor deposition. It is used for abrasive and wear-resistant applications, often as coatings or in cutting tools.

In polymers, microcrystalline describes small crystalline domains within a polymer matrix, giving a partially crystalline texture that influences mechanical properties, strength, and processing behavior.

Overall, microcrystalline is a descriptive term for materials where crystallinity exists at a very small scale, affecting texture, optical properties, and performance across various fields.