Huminite

Huminite is a maceral group found in coal and other dispersed organic matter. Maceral groups are microscopic constituents of coal, analogous to minerals in rocks. Huminite comprises the humic macerals, which are derived from the degradation of lignin and cellulose within plant tissues. These are the most abundant maceral group in low-rank coals, such as lignite and subbituminous coal.

The huminite group is further subdivided into several types, including humodetrinite, huminite proper, and textinite. Humodetrinite is characterized by its fine-grained, detrital nature, often appearing as fragments or lamellae. Huminite proper typically retains some evidence of original plant cell structure, though it is often degraded and compressed. Textinite represents huminite that has preserved distinct cellular textures.

Huminite macerals are generally characterized by their high volatile matter content and relatively low reflectance compared to other maceral groups like vitrinite and inertinite. Their chemical composition is rich in oxygen-containing functional groups, which contributes to their reactivity. The abundance and type of huminite can significantly influence the physical and chemical properties of low-rank coals, affecting their behavior during processes such as combustion, gasification, and liquefaction. The study of huminite is crucial for understanding coalification processes and the genesis of sedimentary organic matter.