Liptinite is an umbrella term used in coal geology, referring to the finely-ground and macerated remains found in coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

 deposits. It replaced the term Exinite as one of the four categories of kerogen
Kerogen is a mixture of organic chemical compounds that make up a portion of the organic matter in sedimentary rocks. It is insoluble in normal organic solvents because of the huge molecular weight of its component compounds. The soluble portion is known as bitumen. When heated to the right...

. Liptinites were originally formed by spores, pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...

, dinoflagellate
The dinoflagellates are a large group of flagellate protists. Most are marine plankton, but they are common in fresh water habitats as well. Their populations are distributed depending on temperature, salinity, or depth...

 cysts, leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

 cuticles, and plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

 resins and waxes.

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 exines 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. It is a Type II kerogen....

, 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....

, alginite
Alginite is a component of some types of kerogen alongside amorphous organic matter. Alginite consists of organic-walled marine microfossils, distinct from inorganic -walled microfossils that comprise diatomaceous earth. At least two forms of alignite are distinguishable, "alginite A" and...

Telalginite is a structured organic matter in sapropel, composed of large discretely occurring colonial or thick-walled unicellular algae such as Botryococcus, Tasmanites and Gloeocapsomorpha prisca. Telalginite is present in large algal bodies. It fluoresce brightly in shades of yellow under...

 and lamalginite
Lamalginite is a structured organic matter in sapropel, composed of thin-walled colonial or unicellular algae that occur as distinct laminae, cryptically interbedded with mineral matter. It displays few or no recognisable biologic structures. Lamalginite fluoresce brightly in shades of yellow...

), resinite.

Macerals (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.
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