Which type of limestone is known for having the chemical formula CaCO3?

Calcitic limestone is indeed characterized by its primary chemical composition, which is calcium carbonate (CaCO3). This limestone is primarily formed from the accumulation of calcite, a mineral that is a significant component of the sedimentary rock. The presence of pure calcium carbonate gives calcitic limestone its distinct chemical properties and plays a critical role in various applications, including agriculture, where it is used to improve soil pH and provide calcium to crops.

In contrast, dolomitic limestone contains not only calcium carbonate but also magnesium carbonate, leading to a different chemical formula (CaMg(CO3)2). Calcium silicate is a compound that does not contain carbonate and is generally not classified as a limestone, while hydrated lime involves calcium hydroxide (Ca(OH)2) and is produced by the reaction of quicklime with water. Thus, the distinctive feature of calcitic limestone being composed solely of calcium carbonate makes it the correct answer in this context.