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Gypsum vs. Anhydrite: What's the Difference?

Edited by Huma Saeed || By Sumera Saeed || Published on November 23, 2023
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, whereas anhydrite is its anhydrous form, lacking water in its structure.

Key Differences

Gypsum, a widely used mineral, is known for its softness and is composed of calcium sulfate dihydrate. Anhydrite, on the other hand, is a hard mineral, the anhydrous form of calcium sulfate, and is often found in salt deposits.
Sumera Saeed
Nov 23, 2023
In terms of usage, gypsum is a key ingredient in plaster and drywall, owing to its bonding properties and ease of shaping. Anhydrite, due to its hardness and lack of water, is less versatile in construction but is valuable in the manufacture of certain cements.
Sumera Saeed
Nov 23, 2023
Gypsum can easily be converted to anhydrite by heating, a process that removes water. Conversely, anhydrite can absorb water to convert back into gypsum, a property used in some industrial processes.
Huma Saeed
Nov 23, 2023
The occurrence of gypsum is often in sedimentary rock formations and can be mined in large quantities. Anhydrite is also found in sedimentary basins but is less common and usually deeper underground.
Janet White
Nov 23, 2023
Both minerals are essential in geological studies for understanding sedimentary environments, with gypsum indicating a more watery past environment compared to the drier conditions indicated by anhydrite.
Sumera Saeed
Nov 23, 2023
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Comparison Chart

Chemical Composition

Calcium sulfate dihydrate (CaSO4·2H2O)
Calcium sulfate anhydrous (CaSO4)
Sumera Saeed
Nov 23, 2023

Hardness

Soft, can be scratched with a fingernail
Harder than gypsum
Sumera Saeed
Nov 23, 2023

Usage in Industry

Used in plaster, drywall, and as a fertilizer
Used in cement and as a drying agent
Sumera Saeed
Nov 23, 2023

Water Content

Contains water molecules in its structure
Lacks water in its crystal structure
Harlon Moss
Nov 23, 2023

Formation Conditions

Forms in watery environments
Indicates drier sedimentary conditions
Sumera Saeed
Nov 23, 2023
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Gypsum and Anhydrite Definitions

Gypsum

Used in sculpture and art for casting molds.
Artists often use gypsum to create detailed molds.
Aimie Carlson
Nov 15, 2023

Anhydrite

A hard mineral consisting of anhydrous calcium sulfate.
Anhydrite deposits were found beneath the salt dome.
Huma Saeed
Nov 15, 2023

Gypsum

A mineral used as a fertilizer for its high sulfur and calcium content.
Gypsum was added to the soil to improve its quality.
Janet White
Nov 15, 2023

Anhydrite

Anhydrite can transform into gypsum when exposed to water.
Over time, the anhydrite absorbed moisture and became gypsum.
Harlon Moss
Nov 15, 2023

Gypsum

A soft white or gray mineral used in making plaster.
The walls were made of gypsum plaster.
Sumera Saeed
Nov 15, 2023

Anhydrite

Used as a drying agent due to its moisture-absorbing properties.
Anhydrite was used to dry out the damp soil.
Sumera Saeed
Nov 15, 2023

Gypsum

Gypsum is found in sedimentary rock formations.
The geologist discovered gypsum layers in the rock strata.
Harlon Moss
Nov 15, 2023

Anhydrite

Used in the manufacture of certain types of cement.
The factory utilized anhydrite as a cement additive.
Janet White
Nov 15, 2023

Gypsum

Gypsum boards are used in construction for drywall.
The contractor used gypsum boards for the interior walls.
Aimie Carlson
Nov 15, 2023

Anhydrite

Found in salt domes and sedimentary basins.
Anhydrite layers indicated a dry period in the region's geological history.
Sumera Saeed
Nov 15, 2023

Gypsum

A widespread colorless, white, or yellowish mineral, CaSO4·2H2O, used in the manufacture of plaster of Paris, various plaster products, and fertilizers.
Sumera Saeed
Nov 14, 2023

Anhydrite

A colorless, white, gray, blue, or lilac mineral of anhydrous calcium sulfate, CaSO4, occurring as layers in gypsum deposits.
Sumera Saeed
Nov 14, 2023

Gypsum

A mineral consisting of hydrated calcium sulphate. When calcinated, it forms plaster of Paris.
Sumera Saeed
Nov 14, 2023

Anhydrite

(mineral) An evaporite mineral made of anhydrous calcium sulfate.
Sumera Saeed
Nov 14, 2023

Gypsum

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.
Sumera Saeed
Nov 14, 2023

Anhydrite

A mineral of a white or a slightly bluish color, usually massive. It is anhydrous sulphate of lime, and differs from gypsum in not containing water (whence the name).
Sumera Saeed
Nov 14, 2023

Gypsum

A common white or colorless mineral (hydrated calcium sulphate) used to make cements and plasters (especially plaster of Paris)
Sumera Saeed
Nov 14, 2023

FAQs

What is anhydrite's main chemical composition?

Anhydrite is composed of anhydrous calcium sulfate.
Aimie Carlson
Nov 23, 2023

Is gypsum soft or hard?

Gypsum is quite soft and can be scratched with a fingernail.
Sumera Saeed
Nov 23, 2023

How is gypsum important in agriculture?

It's used as a soil amendment for its sulfur and calcium content.
Aimie Carlson
Nov 23, 2023

Does gypsum contain water in its structure?

Yes, gypsum contains water molecules in its structure.
Janet White
Nov 23, 2023

Is anhydrite used as a drying agent?

Yes, its moisture-absorbing properties make it a good drying agent.
Aimie Carlson
Nov 23, 2023

What is gypsum primarily used for?

Gypsum is used in making plaster, drywall, and as a fertilizer.
Sumera Saeed
Nov 23, 2023

Can anhydrite be used in construction?

Anhydrite is less common in construction, often used in cement.
Huma Saeed
Nov 23, 2023

Can gypsum be converted to anhydrite?

Yes, by heating and removing water, gypsum becomes anhydrite.
Harlon Moss
Nov 23, 2023

What indicates the presence of gypsum in sedimentary rocks?

Layers of gypsum in rocks indicate past watery environments.
Sumera Saeed
Nov 23, 2023

Does anhydrite have any industrial applications?

It's used in cement manufacture and as a drying agent.
Aimie Carlson
Nov 23, 2023

Where is anhydrite typically found?

Anhydrite is found in salt domes and deep sedimentary basins.
Sumera Saeed
Nov 23, 2023

Is anhydrite harder than gypsum?

Yes, anhydrite is harder than gypsum.
Aimie Carlson
Nov 23, 2023

How is gypsum used in art?

It's used in sculpture and casting molds.
Aimie Carlson
Nov 23, 2023

What color is gypsum?

Gypsum is typically white or gray.
Janet White
Nov 23, 2023

Can gypsum be used in drywall production?

Yes, it's a primary material in drywall.
Aimie Carlson
Nov 23, 2023

Can anhydrite transform into gypsum?

Yes, anhydrite can become gypsum when exposed to water.
Sumera Saeed
Nov 23, 2023

What geological information does anhydrite provide?

It indicates drier sedimentary conditions in the past.
Harlon Moss
Nov 23, 2023

Are gypsum and anhydrite found together?

They can be found in similar environments but indicate different conditions.
Janet White
Nov 23, 2023

Is anhydrite soluble in water?

It's less soluble than gypsum but can absorb water.
Sumera Saeed
Nov 23, 2023

Is gypsum a common mineral?

Yes, it's a common and widely mined mineral.
Sumera Saeed
Nov 23, 2023
About Author
Written by
Sumera Saeed
Sumera is an experienced content writer and editor with a niche in comparative analysis. At Diffeence Wiki, she crafts clear and unbiased comparisons to guide readers in making informed decisions. With a dedication to thorough research and quality, Sumera's work stands out in the digital realm. Off the clock, she enjoys reading and exploring diverse cultures.
Edited by
Huma Saeed
Huma is a renowned researcher acclaimed for her innovative work in Difference Wiki. Her dedication has led to key breakthroughs, establishing her prominence in academia. Her contributions continually inspire and guide her field.

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