It can be used as a fertilizer, is the main constituent in many forms of plaster and in blackboard chalk, and is widely mined. Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate.It can be used as a fertilizer, is the main constituent in many forms of plaster and in blackboard chalk, and is widely mined.
Gypsum uses include: manufacture of wallboard, cement, plaster of Paris, soil conditioning, a hardening retarder in Portland cement. Varieties of gypsum known as satin spar and alabaster are used for a variety of ornamental purposes, however their low hardness limits their durability. Gypsum is an evaporite mineral most commonly found in layered sedimentary deposits in association with halite, anhydrite, sulfur, calcite and dolomite. Gypsum (CaSO 4. 2H 2 O) is very similar to Anhydrite (CaSO 4). The chemical difference is that gypsum contains two waters and anhydrite is without water Gypsum is an inert, safe mineral that has been used in a variety of applications for centuries. It was used as plaster in the Egyptian pyramids, and today it is most commonly used in homes and commercial buildings, as gypsum wallboard. The average person eats about 28 pounds of gypsum in a lifetime. When gypsum rock is crushed and the water removed, it can be used to make plaster of paris, commonly used in industry. Ground gypsum is also used as a soil conditioner. A non-toxic mineral, gypsum can be helpful to humans, animals, plant life, and the environment. While the majority of gypsum produced in North America is used to manufacture gypsum panels or building plasters, gypsum can also be used: 1  As a soil additive (sometimes called land plaster) to improve the soil’s workability and receptivity to moisture, and to overcome the corrosive effect of alkalinity.  Gypsum has many other uses, too. In fact, it is used as a filler ingredient in many foods. The average person eats about 28 pounds of gypsum in a lifetime. When gypsum rock is crushed and the water removed, it can be used to make plaster of paris, commonly used in industry. Ground gypsum is also used as a soil conditioner. Chemically, gypsum rock is calcium sulfate with two molecules of water Chemically known as “calcium sulfate dihydrate,” gypsum contains calcium, sulfur bound to oxygen, and water. Gypsum is an abundant mineral and takes forms including alabaster—a material used in decoration and construction as far back as ancient Egypt.  Gypsum: Gypsum is actually an element called calcium sulfate that is used to loosen up stubborn, compacted or clay soils. Gypsum works by pulling together clay particles in the soil to make bigger particles, creating porous spaces for air, water and plant roots.  Gypsum crystals in the Cave of the Crystals in Mexico. Note person for scale. Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO 4 ·2H 2 O. It can be used as a fertilizer, is the main constituent in many forms of plaster and in blackboard chalk, and is widely mined. The word gypsum is derived from the Greek word γύψος (gypsos), chalk or plaster. Because the quarries of the Montmartre district of Paris have long furnished burnt gypsum (calcined gypsum) used for various purposes, this dehydrated gypsum became known as plaster of Paris. Gypsum is the more common name for a mineral compound called calcium sulphate dihydroxide, or sulphate of lime. It is generally found underground near deposits of limestone or other minerals formed by evaporation. One of the most common forms of raw gypsum is a pure white crystal called alabaster. 
http://geology.com/minerals/gypsum.shtml http://www.nationalgypsum.com/about/gypsum-rock.htm https://www.gypsum.org/about/gypsum-101/uses-gypsum/ http://www.nationalgypsum.com/about/gypsum-rock.htm https://www.gypsum.org/about/gypsum-101/what-is-gypsum/ http://www.homedepot.com/c/gypsum_lime_fertilizer_HT_BG_OD https://en.wikipedia.org/wiki/Gypsum http://www.wisegeek.org/what-is-gypsum.htm
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