Here's why:

* Detrital sedimentary rocks are formed from the accumulation and cementation of fragments of other rocks, minerals, and organic matter.

* Sandstone is specifically formed from sand-sized grains (0.0625 to 2 millimeters in diameter), typically composed of quartz, feldspar, or rock fragments.

Other examples of detrital sedimentary rocks include:

* Conglomerate: Made up of rounded gravel-sized fragments.

* Breccia: Made up of angular gravel-sized fragments.

* Shale: Made up of very fine-grained clay and silt particles.