What is Gypsum?

Gypsum is a soft sulphate mineral composed of calcium sulphate dehydrate. It is commonly found in sedimentary rock formations and is mined in many parts of the world. Gypsum is known for its white or greyish colour, and it can sometimes appear translucent. When it is heated, gypsum loses its water content and becomes plaster of Paris, a material that is widely used in construction and art.

Gypsum is relatively abundant in the UK, with significant deposits found in several regions. The UK has a long history of gypsum mining and remains one of Europe’s leading producers, supplying both domestic industries and export markets. There are major active mines in the East Midlands, Yorkshire, and Northern Ireland.

What is gypsum used for?

Gypsum has a wide range of applications across various industries, including construction, agriculture, medicine, and art. Its versatility comes from its ability to be crushed, powdered, or heated to create different products. Gypsum is one of the most useful minerals due to its softness, solubility, and ability to form strong bonds when mixed with water. It has been used for thousands of years, from ancient Egyptian pyramids to modern skyscrapers and remains an essential material today.

Uses of gypsum

Gypsum is used in many ways, such as:

Construction

Gypsum is used in drywall, otherwise known as plasterboard, cement, and plaster and is used to form interior walls and ceilings. It is fire-resistant as it contains water molecules that release as steam when heated, slowing the spread of fire. It is lightweight, and easy to cut and install and it also has soundproofing properties. Gypsum powder is pressed between two sheets of paper to form panels. For traditional plaster it is used for smooth wall finishes before drywall became common.

Plaster of Paris is made by heating gypsum to remove water. When it is mixed with water, it hardens quickly which makes it ideal for moulds, sculptures, and decorative ceilings. Gypsum is added to cement as it controls the setting time, slowing hardening for workability. Gypsum-based mixes can create smooth, flat floors before installing tiles or hardwood.

Agriculture

ypsum acts as a soil conditioner in order to improve soil structure and provide calcium and sulphur. Clay soils can be dense and poorly drained and sodic soils have excess sodium, gypsum fixes this by loosening compacted clay as calcium replaces sodium, improving structure, it also reduces soil salinity and helps flush out excess salts. It also enhances water infiltration as it reduces runoff and erosion. Gypsum does not alter soil pH, making it safe for most crops. It also reduces aluminium toxicity in acidic soils as in acidic soils, aluminium can stunt root growth but gypsum binds aluminium, making it less harmful to plants.

Medical

It is used in casts for broken bones, known as plaster of Paris. Plaster of Paris hardens when it is wet, creating a lightweight, durable cast. It is gradually being replaced by fiberglass casts but it is still widely used. It is also used to create accurate moulds of teeth for crowns, dentures, and braces. Custom-moulded gypsum also supports injured limbs during healing.

Art and sculpture

Gypsum is used for making moulds and sculptures. Gypsum has been a fundamental material in art for thousands of years, valued for its workability, fine detail retention, and durability. From ancient sculptures to modern casting techniques, gypsum, particularly plaster of Paris remains a favourite among artists, sculptors, and conservators. Artists like gypsum because it is affordable as it is cheaper than marble or bronze, it is fast-setting, it captures fine textures like fingerprints, or fabric folds, and it can be easily painted and accepts acrylics, oils, and gold leaf.

The food industry

Gypsum is added to foods as a calcium supplement and firming agent (E516). Gypsum plays several important roles in food production, where it’s valued for its calcium content, pH-stabilising properties, and to improve texture. The food industry relies on gypsum because it is natural and non-toxic as a mined mineral, and is not a synthetic chemical, it also improves texture, nutrition, and processing and it is cost-effective.

Industrial

It is used in making chalk, toothpaste, and even as a filler in paper and textiles. Its unique properties including whiteness, softness, chemical stability, and binding capacity make it valuable for producing everyday consumer goods. It demonstrates gypsum’s versatility as more than just a construction material, it’s a critical component in products we use daily, from classroom chalk to premium papers and even our toothpaste. Its combination of performance characteristics, abundance, and low cost ensure continued industrial usage.

How is gypsum used?

Gypsum is a versatile mineral with a wide range of applications across various industries due to its unique properties, such as its ability to harden when mixed with water and its soft, workable nature. Gypsum is extracted from the earth through both open-pit mining and underground mining methods, depending on the depth and quality of the gypsum deposits.

Before mining begins, geologists survey potential gypsum deposits using core drilling, and geological assessments to determine the size, purity, and accessibility of the gypsum beds. Once a suitable site is found, the area is cleared of vegetation, and access roads are developed for heavy machinery.

Gypsum can be mined using two primary techniques:

• Open-pit mining, also known as surface mining – this method is used when gypsum deposits are located near the surface. Large excavators, bulldozers, and front-end loaders remove overburden which is any soil, rock, and other materials covering the gypsum. Once exposed, the gypsum is extracted using explosives, if necessary or by using heavy equipment like draglines and power shovels. The extracted gypsum is then loaded onto trucks and taken to processing plants.
• Underground mining – when gypsum deposits are deep underground, miners use room-and-pillar mining techniques. Tunnels are dug into the deposit, leaving large pillars of gypsum to support the roof and prevent collapses. Miners use drilling and blasting or continuous mining machines in order to extract the gypsum, which is then transported to the surface using conveyor belts or trucks.

After extraction, raw gypsum is crushed and screened in order to remove impurities like clay, rock, and sand. It may then be dried in a kiln at low temperatures to remove excess moisture, producing calcined gypsum, otherwise known as plaster of Paris. For construction-grade gypsum, the material is further ground into a fine powder and mixed with additives to improve its properties before being pressed into drywall sheets or other products.

Gypsum mining operations must follow environmental regulations in order to minimise land disruption, water pollution, and habitat destruction. Many mines implement reclamation plans, where excavated areas are refilled, replanted, or repurposed after mining ends. Gypsum extraction is a carefully managed process that ensures a steady supply of this valuable mineral for construction, agriculture, medicine, and other industries.

In construction, Gypsum is processed into drywall sheets for walls and ceilings. It is also mixed into cement to control setting time. Drywall sheets are essential for creating smooth, fire-resistant walls and ceilings in buildings. Gypsum is also added to cement and plaster to regulate the setting time, ensuring that these materials harden at a controlled rate for better workability and durability.

In agriculture, gypsum plays an important role in soil improvement. Farmers apply gypsum powder to fields to break up dense clay soils, enhancing drainage and root growth. Additionally, gypsum helps reduce soil salinity by displacing excess sodium, which improves soil structure and promotes healthier crop yields.

In the medical field, gypsum is used to create orthopaedic casts for stabilising broken bones. When mixed with water, gypsum forms a paste that hardens into a solid, lightweight cast, providing support and protection during the healing process.

In art and sculpture, gypsum is valued for its ease of shaping and fine detail retention. Artists use it to make moulds for casting metals, ceramics, and other materials, as well as carving it directly into decorative sculptures and architectural ornaments.

Why is gypsum used?

Gypsum is popular because it is fire-resistant, making it ideal for building materials, it improves soil quality by adding essential nutrients. It is non-toxic and safe for medical and food applications, and it is abundant and cost-effective, making it widely available.

When exposed to heat, gypsum releases water molecules in the form of steam, which helps to slow down the spread of flames. This makes gypsum-based drywall (plasterboard) a crucial material for building walls and ceilings, enhancing fire safety in homes, offices, and industrial structures. Additionally, gypsum is lightweight, easy to install, and provides excellent sound insulation.

In agriculture, gypsum is highly beneficial for improving soil structure and fertility. It helps break up compacted clay soils, allowing better water drainage and root penetration. Gypsum also reduces soil salinity by replacing excess sodium with calcium, which promotes healthier plant growth. It also provides important nutrients like calcium and sulphur, which are vital for crop development without altering soil PH.

Gypsum is chemically inert and non-toxic, making it safe for medical and food-related uses. In medicine, gypsum plaster is used to make orthopaedic casts for fractures because it hardens quickly, is lightweight, and allows X-ray penetration for monitoring bone healing. In the food industry, gypsum is used as a coagulant in tofu production and as a dough conditioner in baking in order to improve texture.

Gypsum is a naturally abundant mineral found in large deposits worldwide, making it an affordable and sustainable material. Its low extraction and processing costs contribute to its widespread use in construction, agriculture, and manufacturing. Unlike synthetic alternatives, gypsum is eco-friendly and can be recycled, further enhancing its economic and environmental benefits.

Beyond its practical applications, gypsum is valued in art and manufacturing for its workability. When mixed with water, it forms a malleable paste that hardens into a durable solid, making it ideal for sculpting, mould-making, and decorative plasterwork. It is also used in industrial settings, such as in cement production to control setting time and in water treatment in order to remove impurities.

Gypsum’s unique combination of fire resistance, soil-enhancing properties, non-toxicity, affordability, and versatility makes it an important part of many industries. Its natural abundance and eco-friendly characteristics further ensure its continued use in sustainable construction, agriculture, medicine, and beyond.

Impacts of using gypsum

Positive impacts include:

• Environmental benefits – gypsum helps to reduce soil erosion and water runoff in agriculture. Gypsum improves soil structure by reducing surface crusting, allowing for better water infiltration. It also prevents clay dispersion, which helps to stabilise soil and reduces erosion caused by wind and rain. In areas where soils has high sodium content, gypsum replaces sodium with calcium, improving permeability and reducing runoff. It also mitigates water pollution by reducing phosphorus runoff from fertilisers and helps prevent excessive algae growth in water bodies. It binds with heavy metals, for example lead in contaminated soils, reducing their leaching into groundwater. Gypsum also improves soil health, enhancing root growth by reducing soil compaction and helps retain moisture in drought-prone areas.
• Economic benefits – gypsum is a cost-effective and versatile material, supporting multiple industries like construction and farming. The global gypsum market was valued at $2.8 billion in 2023, driven by construction and agriculture demand.
• Health benefits – gypsum provides calcium in food and helps heal bone fractures. Gypsum has direct and indirect health advantages. It is a dietary calcium source and is used as a calcium supplement in tofu production, it is used in baked goods to strengthen the dough and is used in fortified drinks and cereals. There are indirect health benefits, by improving soil quality, gypsum contributes to more nutritious crops, reduces heavy metal uptake in plants, making food safer. For example, in regions with excess fluoride in water, gypsum-treated soils reduce fluoride absorption in crops.

Negative impacts includes:

• Mining effects – gypsum extraction can disturb ecosystems if not managed sustainably. Open-pit gypsum mining involves clearing large land areas, leading to deforestation, soil erosion, and loss of biodiversity. Mining operations can permanently change the topography, leaving behind large pits or unstable terrain that may not fully recover even after reclamation efforts. Excavation can interfere with groundwater systems, affecting local water supplies and aquatic ecosystems.
• Dust pollution – processing gypsum can create dust, affecting air quality. Crushing and grinding gypsum releases fine dust particles into the air, contributing to respiratory problems in workers and nearby residents. When gypsum is heated at high temperatures, for example in cement production, it can release sulphur dioxide, a harmful gas that contributes to acid rain and respiratory illnesses.
• Health risks for workers – prolonged exposure to gypsum dust can cause silicosis, bronchitis, and other lung conditions in miners and construction workers. Handling dry gypsum powder without protective clothing and equipment can lead to skin dryness, irritation, and eye discomfort. Gypsum is low-toxicity but requires basic precautions in order to avoid dust inhalation, skin or eye irritation, and slip or fall risks. Proper PPE and workplace controls can minimise most hazards.
• Water contamination – rainwater can wash gypsum dust and mining by-products into nearby rivers and streams, increasing water hardness and harming aquatic life.
• Chemical leaching – some gypsum deposits contain trace amounts of heavy metals, which can leach into groundwater if not properly managed.
• Waste disposal issues – construction waste, such as discarded drywall, makes up a significant portion of landfill material. When gypsum breaks down in landfills, it can produce hydrogen sulphide, which is a toxic and foul-smelling gas. While gypsum is recyclable, many regions lack proper recycling programs, leading to unnecessary waste accumulation.
• Overuse in soil – excessive gypsum can lead to nutrient imbalances in farmland. Over-application of gypsum in farming can lead to calcium accumulation, which may disrupt soil nutrient balance and harm certain crops. Low-quality gypsum if used in agriculture might contain impurities that could enter the food chain.

In the UK, gypsum safety is regulated under several key laws and regulations, focusing on workplace exposure, construction standards, waste management, and environmental protection. Workplace Health & Safety Control of Substances Hazardous to Health (COSHH) Regulations 2002 applies to employers and workers who are handling gypsum dust. Health and Safety at Work Act 1974 (HSWA) sets out a general duty to ensure worker safety, including safe handling of gypsum. Employers must provide training on gypsum dust risks.

What is gypsum made from?

Gypsum forms naturally when water evaporates from mineral-rich lakes or seas, leaving behind calcium sulphate deposits. It can also be produced synthetically as a by-product of industrial processes, such as flue-gas desulphurisation in power plants. Gypsum primarily forms through evaporation in shallow seas, salt lakes, and arid environments. When seawater or mineral-rich lake water evaporates, dissolved calcium and sulphate ions combine to form gypsum crystals. This occurs in dry climates where evaporation rates exceed rainfall.

Over millions of years, gypsum accumulates in sedimentary beds, often found alongside rock salt and anhydrite, a dehydrated form of gypsum. Major deposits of this exist in the USA, Iran, China, Spain, and Mexico. In some cases, gypsum forms from volcanic gases reacting with limestone or from hot springs depositing sulphate minerals.

As well as natural deposits, gypsum can be produced as a by-product of industrial processes, for example coal-fired power plants release sulphur dioxide, which is a pollutant. In order to reduce emissions, plants use scrubbers that react sulphur dioxide with limestone, producing synthetic gypsum. This type is chemically identical to natural gypsum and is widely used in drywall and cement.

When phosphate rock is processed into fertiliser, it releases phosphor-gypsum as a by-product. It contains small amounts of radioactive elements, like radium, limiting its use in construction. It is often stored in large stacks or used in road base materials. Gypsum always contains calcium, sulphur, oxygen, and water molecules, but its structure can vary.

Gypsum is a highly useful mineral, however, responsible mining and usage are necessary in order to minimise its environmental impacts. From strengthening buildings to improving crop yields, gypsum plays a critical role in modern industries while posing minimal health risks when handled properly. Its sustainability and recyclability show its importance in eco-friendly practices. Overall, gypsum is a multipurpose mineral that combines practical utility, safety, and environmental benefits.