Chalk is a distinctive variety of limestone that is soft, whitish, and powdery. Limestone is a common sedimentary rock formed from sediments that were once-living organisms (plants, animals, micro-organisms). Specifically, chalk is composted of trillions of microfossils that accumulated in moderately deep marine environments. It is the same as the rock forming the White Cliffs of Dover.
Chalk will bubble in acid.
Biogenic sedimentary rock.
Size: Hand specimen.
Demonstrates erosion to a smooth oval shape due to movement down rivers and the coastline.
Images are examples of specimens only. Sizes and shapes may vary.