These jumbles of glass and crushed rock are impact breccias. The dark, flattened and twisted fragments in the Ries breccia slab are pieces of impact glass. In samples from older craters such as Gosses Bluff, similar glass pieces have weathered to clay.
Generations of impacts shattered and melted the Moon's crust, welding together new rocks called breccias. In this sample, even the small fragments are composed of still smaller bits of rock. Collected by Apollo 16.