Nongranular

Nongranular is a descriptive term used in geology, soils, and materials science to indicate a texture or structure that lacks distinct, visible grains. The term is often applied when the material is amorphous or when any crystalline elements are too small to resolve with the unaided eye. In many contexts nongranular textures are described as glassy, cryptocrystalline, or microcrystalline.

In geology and petrology, nongranular textures occur in volcanic glasses such as obsidian and in rapidly cooled rocks where minerals fail to crystallize into discernible grains. By contrast, granitic or crystalline rocks display angular or euhedral grains that can be seen with the naked eye or under a light microscope. Nongranular textures may also refer to rocks with a very fine-grained matrix in which individual crystals are not resolvable.

In soils, nongranular can describe a structural class where the soil mass lacks discrete granular ped structures; instead it may be massive or featureless. This usage contrasts with granular, blocky, or prismatic soil structures that exhibit recognizable aggregates or pore spaces.

In materials science, nongranular often implies an amorphous solid such as glass, or a metallic glass, where atoms lack long-range order. Such materials typically exhibit isotropic properties and distinctive mechanical behavior compared with crystalline, grain-based materials.

Notes: The meaning of nongranular varies by field and context. When grains are too small to resolve, terms like microcrystalline or cryptocrystalline may be used to describe the material more precisely. The term is primarily descriptive rather than a formal classification.