Plaster of Paris is a quick-setting material made from gypsum, a naturally occurring mineral. When gypsum is heated to about 150 degrees Celsius, it loses water and becomes a fine powder. When mixed with water, it forms a paste that hardens as it dries, making it useful for various applications, including art, construction, and medical casts. This versatile substance is named after the large deposits of gypsum found in Montmartre, a district in Paris. It is commonly used for creating molds, sculptures, and decorative elements in buildings. Additionally, Plaster of Paris is valued for its smooth finish and ease of use.