Chalk vs. Gypsum — What's the Difference?

To rub or cover with chalk, as the tip of a billiard cue.

A protective layer applied to walls or ceilings.

A soft, white limestone, primarily composed of calcite.

A soft sulfate mineral consisting of calcium sulfate dihydrate.

A stick of this limestone or a similar substance used for writing or drawing.

A rock or sediment containing this mineral.

Chalk is a soft, white, porous, sedimentary carbonate rock, a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton which had fallen to the sea floor. Chalk is common throughout Western Europe, where deposits underlie parts of France, and steep cliffs are often seen where they meet the sea in places such as the Dover cliffs on the Kent coast of the English Channel.

To apply or treat with gypsum.

A white soft earthy limestone (calcium carbonate) formed from the skeletal remains of sea creatures.

A substance used in making plaster, drywall, and fertilizers.

Short for French chalk

Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard/sidewalk chalk, and drywall. A massive fine-grained white or lightly tinted variety of gypsum, called alabaster, has been used for sculpture by many cultures including Ancient Egypt, Mesopotamia, Ancient Rome, the Byzantine Empire, and the Nottingham alabasters of Medieval England.

Write or draw with chalk

A widespread colorless, white, or yellowish mineral, CaSO4·2H2O, used in the manufacture of plaster of Paris, various plaster products, and fertilizers.

Charge (drinks bought in a pub or bar) to a person's account

A mineral consisting of hydrated calcium sulphate. When calcinated, it forms plaster of Paris.

A soft compact calcite, CaCO3, with varying amounts of silica, quartz, feldspar, or other mineral impurities, generally gray-white or yellow-white and derived chiefly from fossil seashells.

A mineral consisting of the hydrous sulphate of lime (calcium). When calcined, it forms plaster of Paris. Selenite is a transparent, crystalline variety; alabaster, a fine, white, massive variety.

A piece of chalk or chalklike substance in crayon form, used for marking on a blackboard or other surface.

A common white or colorless mineral (hydrated calcium sulphate) used to make cements and plasters (especially plaster of Paris)

(Games) A small cube of chalk used in rubbing the tip of a billiard or pool cue to increase its friction with the cue ball.

A mark made with chalk.

Chiefly British A score or tally.

To mark, draw, or write with chalk

To make pale; whiten.

To treat (soil, for example) with chalk.

(uncountable) A soft, white, powdery limestone (calcium carbonate, CaCO3).

(countable) A piece of chalk, or nowadays processed compressed gypsum (calcium sulfate, CaSO4), that is used for drawing and for writing on a blackboard (chalkboard).

Tailor's chalk.

A white powdery substance used to prevent hands slipping from holds when climbing, or losing grip in weight-lifting or gymnastics, sometimes but not always limestone-chalk, often magnesium carbonate (MgCO3).

A platoon-sized group of airborne soldiers.

The favorite in a sporting event.

The prediction that there will be no upsets, and the favored competitor will win.

To apply chalk to anything, such as the tip of a billiard cue.

To record something, as on a blackboard, using chalk.

To use powdered chalk to mark the lines on a playing field.

(figuratively) To record a score or event, as if on a chalkboard.

To manure (land) with chalk.

To make white, as if with chalk; to make pale; to bleach.

A soft, earthy substance, of a white, grayish, or yellowish white color, consisting of calcium carbonate, and having the same composition as common limestone.

Finely prepared chalk, used as a drawing implement; also, by extension, a compound, as of clay and black lead, or the like, used in the same manner. See Crayon.

To rub or mark with chalk.

To manure with chalk, as land.

To make white, as with chalk; to make pale; to bleach.

A soft whitish calcite

A pure flat white with little reflectance

Amphetamine used in the form of a crystalline hydrochloride; used as a stimulant to the nervous system and as an appetite suppressant

A piece of chalk (or similar substance) used for writing on blackboards or other surfaces

Write, draw, or trace with chalk

A mark made using this substance.

A cue tip's substance in billiards and pool.

To draw or write with chalk.

Gypsum is used to make wallboard or drywall.

While the mineral itself isn't typically consumed, it's used in food processing, like in tofu production.

Gypsum remains unaffected when exposed to acid.

Yes, Chalk can be used for drawing on surfaces like pavements.

Yes, Chalk is used in the production of lime and cement.

Yes, both Chalk and Gypsum are soft and can be easily scratched.

Chalk is not very soluble in water.

Chalk is primarily composed of calcium carbonate.

Gypsum can range from white to gray and can even be transparent.

Chalk deposits are found in regions that were once under the sea, like the white cliffs of Dover.

Chalk fizzes when it contacts acid due to carbon dioxide release.

Gypsum forms from the evaporation of saline water, leading to its crystallization.

Chalk is typically white.

Yes, Gypsum can be applied to soils to improve their texture and drainage.

Gypsum has low solubility in water but can dissolve over time.