What is the stone crusher?

stone - a lump or mass of hard consolidated mineral matter; "he threw a rock at me"

rock

natural object - an object occurring naturally; not made by man

achondrite - a stony meteor lacking chondrules

bedrock - solid unweathered rock lying beneath surface deposits of soil

boulder, bowlder - a large smooth mass of rock detached from its place of origin

calculus, concretion - a hard lump produced by the concretion of mineral salts; found in hollow organs or ducts of the body; "renal calculi can be very painful"

chondrite - a rock of meteoric origin containing chondrules

clastic rock - (geology) a rock composed of broken pieces of older rocks

crystallization, crystal - a rock formed by the solidification of a substance; has regularly repeating internal structure; external plane faces

intrusion - rock produced by an intrusive process

outcrop, outcropping, rock outcrop - the part of a rock formation that appears above the surface of the surrounding land

pebble - a small smooth rounded rock

petrifaction - a rock created by petrifaction; an organic object infiltrated with mineral matter and preserved in its original form

sill - (geology) a flat (usually horizontal) mass of igneous rock between two layers of older sedimentary rock

stepping stone - a stone in a marsh or shallow water that can be stepped on in crossing

tor - a prominent rock or pile of rocks on a hill

wall rock - a rock immediately adjacent to a vein or fault

whinstone, whin - any of various hard colored rocks (especially rocks consisting of chert or basalt)

xenolith - (geology) a piece of rock of different origin from the igneous rock in which it is embedded

crusher - a device that crushes something

device - an instrumentality invented for a particular purpose; "the device is small enough to wear on your wrist"; "a device intended to conserve water"

So what is the stone crusher? It’s obvious from this article!