Gypsum

Is a mineral found in crystal as well as masses called gypsum rock.  It is a very soft mineral and it can form pretty, and extremely large colored crystals.

Massive gypsum rock forms within layers of sedimentary rock, typically found in thick beds or layers.

The most significant use for gypsum is for wallboard and plaster products. All modern homes in North America and other developed countries use a great deal of wallboard for interior walls. A small amount of very pure gypsum is used in glass making and other specialized industrial applications.