Chalk is mined for use in industry, such as for quicklime, bricks and builder's putty, and in agriculture, for raising pH in soils with high acidity.

It is also used for "blackboard chalk" for writing and drawing on various types of surfaces, although these can also be manufactured from other carbonate-based minerals, or gypsum.

Chalk is a fine-textured, earthy type of limestone distinguished by its light colour, softness, and high porosity.

[3] While it is similar in appearance to both gypsum and diatomite, chalk is identifiable by its hardness, fossil content, and its reaction to acid (it produces effervescence on contact).

[6][7] It was deposited on extensive continental shelves at depths between 100 and 600 metres (330 and 1,970 ft), during a time of nonseasonal (likely arid) climate that reduced the amount of erosion from nearby exposed rock.

[8] Flint (a type of chert) is very common as bands parallel to the bedding or as nodules in seams, or linings to fractures, embedded in chalk.

[11] The Chalk Group is a European stratigraphic unit deposited during the late Cretaceous Period.

The Champagne region of France is mostly underlain by chalk deposits, which contain artificial caves used for wine storage.

[3] Some of the highest chalk cliffs in the world occur at Jasmund National Park in Germany and at Møns Klint in Denmark.

[17] Chalk of Oligocene to Neogene age has been found in drill cores of rock under the Pacific Ocean at Stewart Arch in the Solomon Islands.

[21] Magnesium carbonate chalk is commonly used as a drying agent to obtain better grip by gymnasts and rock climbers.

[26] Additionally, the small particles of chalk make it a substance ideal for cleaning and polishing.

[32] In gymnastics, rock-climbing, weightlifting and tug of war, chalk — now usually magnesium carbonate — is applied to the hands and feet to remove perspiration and reduce slipping.