• Rocks that form from an accumulation of sediments derived from preexisting rocks and/or organic materials.
• These rocks form by various process that occur on or within the top few kilometers of earth’s crust

• Most sedimentary rocks are made up of solid fragments or sediments, often called “clasts”, that have been weathered or eroded from older rocks.
• Clastic texture rocks are composed of smaller rock fragments called sediments. Classified by their particle size

Pebbles, cobbles and/or boulders some silt sand or clay

Size of particles: from .0006cm to .2cm

Particle size: .00004 to .006 cm

Clay magnified 1,600 times
Particle size: less then .0004 cm

• Often the clasts, such as sand, silt, and pebbles, are cemented together in a process called cementation. This happens as the sediments lose water and the dissolved minerals in the pores of the sediments forming a crystalline mineral material

Chemical sedimentary rock
Crystalline Texture
• When dissolved minerals drop out of water
(precipitate), they form a mass of intergrown or interconnected mineral crystals
• You can see crystals in the rock. The crystals are composed of only one mineral

• No crystals, No rock particles. May have shell or shell fragments in it, or be completely black in color consisting of dead organic material
Limestone
Coal