Inequigranular

Inequigranular is an adjective used to describe a texture or material in which constituent granules or grains vary noticeably in size. The term is formed from Latin roots meaning not equal in grain size, contrasting with equigranular, where grains are roughly uniform in size. Its usage is most common in fields dealing with granular materials, polycrystalline aggregates, and rocks, though it can appear in other contexts describing heterogeneous grain distributions.

In geology and mineralogy, inequigranular textures indicate that crystal sizes within a rock are not uniform. Rocks may display a mixture of large and small grains, or a groundmass with a broad spectrum of grain sizes. This heterogeneity can reflect differences in cooling history, deformation, or crystallization rates. In ceramics and materials science, inequigranular microstructures describe polycrystalline materials with a wide particle-size distribution, which can influence packing density, porosity, strength, and diffusion properties.

In biology or histology, inequigranular is much less common, but may be used informally to describe cytoplasmic granules or other cellular inclusions that vary in size.

Quantifying inequigranularity typically involves assessing the grain-size distribution, using metrics such as mean size, median size, sorting, standard deviation, and skewness, often obtained through image analysis or sieving. See also equigranular, grain-size distribution, porphyrogranular textures, and heterogeneity.