Gypsum is a soft, sedimentary, rock-forming mineral and is composed of calcium sulfate dihydrate with the chemical formula CaSO4*2H2O. It is the most common of all sulfate minerals and forms massive beds in sedimentary rocks as well as thin coatings on volcanic rocks and evaporite deposits.

It is the main constituent of wall board (also known as sheet rock) and can be used as a fertilizer or in the production of bricks and paving material. It has also been used as a sand substitute for building and gardening and is a raw material for the manufacture of blackboard or sidewalk chalk. It is also a natural resource that has been mined and used for thousands of years.

The gypsum mineral crystallizes in two forms; as flattened and twinned, pearl-like, translucent masses called selenite, which is named for the Greek word for moon; and as compact, fibrous aggregates with a satin like appearance that are referred to as alabaster. The fine-grained, white or lightly tinted alabaster Agb99 Link Alternatif  was a popular sculpture stone in Ancient Egypt, Mesopotamia, Rome and Medieval England. The Mohs scale of mineral hardness classifies gypsum as 2 on the hardness scale.

Today gypsum is one of the most commonly mined and processed minerals in the world. It is harvested from large open pit quarries in many countries including Australia, Brazil, India, Pakistan, Iran, Mexico, Spain (the largest producer in Europe), the United States, England and Germany. Large gypsum operations are located at Fort Dodge, Iowa, which sits on one of the largest deposit of gypsum in the world and Plaster City, California, USA; and at Kalannie and East Kutai, Western Australia, Australia. Boral is a leading supplier of gypsum in Australia with a market share of 40%.

Gypsum is an important soil conditioner and is essential for the sustainability of irrigated agriculture. It prevents or corrects sodicity and salinity in most types of soil and enhances water penetration into the soil. It is particularly effective in amending clay soils. It also improves the ability of soil to retain water and nutrient.

NatraMin Cal-S is a cost effective alternative to Gypsum that provides a wider range of benefits for the soil and plant. It acts as a bio-stimulant to increase microbe and worm activity in the soil which in turn helps to produce humus and improve the structure of the soil. It also supplies broad spectrum minerals and trace elements that help avoid nutrient tie up in the soil and assists in making nutrients more available to the plants.