Calcite is a mineral used in many ways, serving as a construction material and aggregate, a pigment, agricultural soil additive and an ingredient in pharmaceutical products. Calcite is most often found in limestone and marble, with many applications in those forms.
Both marble and limestone have been used for centuries as a building block in construction projects. Limestone in particular was the primary construction material for the ancient Egyptians as well as some cultures in Latin America. Marble and calcite have been used in modern times as a component in architectural structures and in various works of art such as sculptures. Marble counter tops are often found in kitchens.
Another use for calcite is as a material that can neutralize acids. Ancient cultures first started the practice of crushing calcite materials such as limestone and spreading them around their fields as a natural soil additive. Crushed limestone can also be added to streams and rivers that have high acidity rates in order to reduce those levels and make the water drinkable.
Calcite is also an active ingredient in calcium carbonate, which is finely crushed limestone that is then combined into tablets or put into certain liquids used to reduce the acid levels in a person's stomach.