Rudite is a general name used for a
sedimentary rocks that are composed of rounded or angular
detrital grains, i.e.
boulders, which are coarser than
size. Rudites include sedimentary rocks composed of both
carbonate grains, i.e.
rudstone. This term is equivalent to the Greek-derived term,
psephite. Rudite was initially proposed by Grabau
 as "rudyte." It is derived from the Latin word, "rudus," for "crushed stone," "rubbish," "debris," and "rubble."
Rudites can be deposited in a variety of nonmarine and marine environments. In nonmarine settings, gravels, which later were lithified to become rudites, accumulated within fluvial channels, within alluvial fans, and as glacial deposits. In marine environments, rudites were deposited along
shorelines as part of
beaches, as basal conglomerates during
marine transgressions, and in the deep sea by slumps and
turbidites. Rudites composed largely of rounded siliciclastic gravel are conglomerates and others composed of angular siliciclastic gravel are breccias.
 gives the following descriptive terms based on grain size, avoiding the use of terms such as
argillaceous which carry an implication of chemical composition. The Greek terms are more commonly used for metamorphosed rocks, and the Latin for unmetamorphosed:
Descriptive size terms