Alginite is a component of some types of kerogen

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...

 alongside amorphous organic matter. Alginite consists of organic-walled marine microfossils, distinct from inorganic (silica)-walled microfossils that comprise diatomaceous earth

Diatomaceous earth

Diatomaceous earth also known as diatomite or kieselgur/kieselguhr, is a naturally occurring, soft, siliceous sedimentary rock that is easily crumbled into a fine white to off-white powder. It has a particle size ranging from less than 1 micrometre to more than 1 millimetre, but typically 10 to...

. At least two forms of alignite are distinguishable, "alginite A" (telalginite

Telalginite

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 "alginite B" (lamalginite

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...

). The "A" form contains morphologically distinguishable microfossils while the "B" form is more amorphous and film-like.