thumb|right|250px|Alginite
Alginite is a component of some types of kerogen alongside amorphous organic matter. Alginite consists of organic-walled marine microfossils, distinct from inorganic (silica)-walled microfossils that comprise diatomaceous earth. The "A" form contains morphologically distinguishable microfossils while the "B" form is more amorphous and film-like.