Gypsum is a key ingredient in:

Gypsum is a key ingredient in plaster of Paris, fertilizers, and construction materials.

Plaster of Paris is a white powder that is made by heating gypsum to 130–180 °C (266–356 °F). It is used to make casts, molds, and other decorative items.

Fertilizers are substances that are added to soil to improve plant growth. Gypsum is a common ingredient in fertilizers because it helps to improve the drainage and aeration of soil.

Construction materials are materials that are used to build structures, such as buildings, bridges, and roads. Gypsum is a common ingredient in construction materials because it is strong and durable.

In conclusion, gypsum is a key ingredient in plaster of Paris, fertilizers, and construction materials. It is a versatile material that has many uses.