* Layers: Sedimentary rocks are formed by the accumulation and cementation of sediments, which naturally form layers.
* Small Grains: These sediments can be small particles like sand, silt, clay, or even the remains of organisms.
Examples of sedimentary rocks with layers and small grains include:
* Sandstone: Formed from cemented sand grains.
* Shale: Formed from compacted clay particles.
* Limestone: Often formed from the accumulation of marine organisms.
Other rock types can also show layering, but the grains are usually much larger:
* Metamorphic rocks: Some metamorphic rocks, like gneiss, have layers formed by the re-crystallization of minerals under heat and pressure. However, the grains in metamorphic rocks are often much larger than those in sedimentary rocks.
Let me know if you have any other details about the rock you're thinking of, and I can help you narrow it down further!