What primary substance is dental stone composed of?

Dental stone, commonly used in forensic and dental applications for making casts and molds, is primarily composed of calcium sulfate. Specifically, dental stone is typically derived from gypsum, which when heated to produce a mixture known as alpha hemihydrate (CaSO4·0.5H2O).

This composition allows dental stone to set quickly and provide a stable, hard model when mixed with water. The physical properties of dental stone, including its ability to capture fine details and resist abrasion, make it ideal for applications in crime scene investigations where precise imprints of dental records or other evidence need to be preserved.

In contrast, the other substances listed have different properties and applications. Calcium carbonate is primarily used in construction and as a dietary supplement, calcium phosphate is often utilized in fertilizers and bone health supplements, and potassium chloride is typically a source of potassium in fertilizers as well as a salt substitute in food preparations. None of these alternatives possess the same chemical characteristics and benefits when used for casting and modeling in forensic contexts as calcium sulfate does.