rudite
/ˈruːdʌɪt/(also rudyte) Geology
noun
Any clastic sedimentary rock composed of grains coarser than sand, i.e. greater than 2 mm (approx. 1/10 inch) in diameter.
Origin
Early 20th century; earliest use found in Amadeus William Grabau (1870–1946). From classical Latin rūdus + -ite.