There are 3 types of rocks in the world: Sedimentary,Metamorphic,and Igneous rocks.
Sedimentary Rocks are rocks made of materials like sand,clay,and/or pebbles that have been cemented together.
Sedimentary Rocks are classified by their Texture, Grain Size , and Composition
The texture of a rock is the size, shape, and arrangement of the grains (for sedimentary rocks) or crystals (for igneous and metamorphic rocks). Sedimentary Rocks have 3 textures: Clastic,Crystalline,and Bioclastic. Clastic sedimentary rocks are rocks composed predominantly of broken pieces or clasts of older weathered and eroded rocks. Clastic sediments or sedimentary rocks are classified based on grain size, clast and cementing material (matrix) composition, and texture. Chemical sedimentary rocks are crystalline, that is made of crystals interlocked with each other. Conceptually, that is the same texture we see in igneous and metamorphic rocks, but NOT in clastic sedimentary rocks. Bioclastic rocks are composed of organic debris such as plants (lignite, coal) or shells (coquina, fossiliferous limestone). Chemical Rocks. Chemical rocks precipitate from water. These include carbonates (limestone and dolomite), evaportites (halite, gypsum, anhydrite), and chert (SiO2). Textures of Sedimentary Rocks.