Plessite is a fine-grained mixture of the minerals kamacite and taenite found in the octahedrite iron meteorites. It occurs in gaps between the larger bands of kamacite and taenite which form Widmanstätten patterns.

Many types of plessite exist and vary in formation mechanism and morphology. Some types of plessite as named by Buchwald's "Iron Meteorites" and Massalski's "Speculations about Plessite" are:

acicular plessite/Type I plessite

black plessite/Type II plessite

cellular plessite/Type III plessite

comb plessite

net plessite/p>

pearlitic plessite

spheroidized plessite