what is the rock name
clay settles in nearly still water
shale
The rock you are referring to is called shale. Shale is a type of sedimentary rock that forms from the accumulation of fine-grained clay particles in still water, such as lakes or deep sea basins. To identify the rock name, it is necessary to understand its characteristics and the geological processes involved.
Here's how you can determine the rock name:
1. Observe the rock's appearance: Shale is typically characterized by its fine-grained texture, composed mostly of clay, silt, and sometimes sand particles. It often appears layered or fissile (breakable in thin sheets) due to the compaction of the sediment.
2. Perform a hardness test: Shale is relatively soft and easily crumbles between your fingers. It can be scratched with a fingernail or a knife, as it has a low hardness compared to harder rocks like quartz or granite.
3. Conduct a sediment test: If you are unsure whether the rock is shale or another type of sedimentary rock, you can perform a sediment test. Place a small piece of the rock in a container of water and stir it vigorously. If the water becomes cloudy or forms a fine suspension of particles, it suggests that the rock contains a significant amount of clay, indicating it is likely shale.
4. Consider the depositional environment: Shale is commonly formed in quiet, low-energy environments such as lake bottoms, river deltas, or deep ocean basins. If the rock was found in or near these areas, it supports the possibility of it being shale.
By considering these factors, you can confidently establish whether the rock name is indeed shale or not.