In coal

geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ea ...

, liptinite is the finely-ground and

macerated Maceration is the process of preparing foods through the softening or breaking into pieces using a liquid. Raw, dried or preserved fruit or vegetables are soaked in a liquid to soften the food, or absorb the flavor of the liquid into the food. I ...

remains found in

coal Coal is a combustible black or brownish-black sedimentary rock, formed as stratum, rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen ...

deposits. It replaced the term exinite as one of the four categories of

kerogen Kerogen is solid, insoluble organic matter in sedimentary rocks. Comprising an estimated 1016 tons of carbon, it is the most abundant source of organic compounds on earth, exceeding the total organic content of living matter 10,000-fold. It ...

. Liptinites were originally formed by

spores In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametop ...

dinoflagellate The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...

cysts,

leaf A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

cuticles, and

plant Plants are predominantly Photosynthesis, photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all curr ...

resins and waxes.Taylor et al., 1998. Organic Petrography. Gebrüder Borntraeger, Berlin. pp. 176 M.C. Stopes introduced the term ''exinite'' in 1935 to describe the microscopic constituent of coal, rich in volatiles and relatively rich in hydrogen, that is represented by the

exine Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gameto ...

s of spores. C.A. Seyler in 1932, however, used the term with its present meaning, designating the following group of macerals:

sporinite Sporinite is a kind of exinite maceral found in coal formed from spores and pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cel ...

cutinite Cutinite is a liptinite maceral formed from terrestrial plant cuticles, and often found in coal deposits. It is classified as a Type II kerogen. References Coal Petrology {{petrology-stub Cutinite is a coal maceral of Liptinite In coal geol ...

, alginite ( telalginite and lamalginite), resinite.

Macerals A maceral is a component, organic in origin, of coal or oil shale. The term 'maceral' in reference to coal is analogous to the use of the term 'mineral' in reference to igneous or metamorphic rocks. Examples of macerals are inertinite, vitrinite, ...

(from the same Latin source as 'macerate') are to coal as minerals are to rock. The term was coined by M. C. Stopes in 1935, who wrote :"The concept behind the word ‘macerals’ is that the complex of biological units represented by a forest tree which crashed into a watery swamp and there partly decomposed and was macerated in the process of coal formation, did not in that process become uniform throughout but still retains delimited regions optically differing under the microscope, which may or may not have different chemical formulae and properties. These organic units, composing the coal mass I propose to call macerals, and they are the descriptive equivalent of the inorganic units composing most rock masses and universally called minerals." The macerals grouped under the term ''exinite'' are not necessarily entirely composed from exines, but appear to have similar technical properties, though little information is so far available on the technological behavior of pure exinite.

References

Petrology Coal Sedimentology {{petrology-stub