structural:summarization
Uses

Limestone is a raw material that is used globally in a variety of different ways including construction, agriculture and as industrial materials. Limestone is very common in architecture, especially in Europe and North America. Many landmarks across the world, including the Great Pyramid and its associated complex in Giza, Egypt, were made of limestone. So many buildings in Kingston, Ontario, Canada were, and continue to be, constructed from it that it is nicknamed the 'Limestone City'. Limestone, metamorphosed by heat and pressure produces marble, which has been used for many statues, buildings and stone tabletops. On the island of Malta, a variety of limestone called Globigerina limestone was, for a long time, the only building material available, and is still very frequently used on all types of buildings and sculptures.

Limestone can be processed into many various forms such as brick, cement, powdered/crushed, or as a filler. Limestone is readily available and relatively easy to cut into blocks or more elaborate carving. Ancient American sculptors valued limestone because it was easy to work and good for fine detail. Going back to the Late Preclassic period (by 200–100 BCE), the Maya civilization (Ancient Mexico) created refined sculpture using limestone because of these excellent carving properties. The Maya would decorate the ceilings of their sacred buildings (known as lintels) and cover the walls with carved limestone panels. Carved on these sculptures were political and social stories, and this helped communicate messages of the king to his people. Limestone is long-lasting and stands up well to exposure, which explains why many limestone ruins survive. However, it is very heavy (density 2.6), making it impractical for tall buildings, and relatively expensive as a building material.

Limestone was most popular in the late 19th and early 20th centuries. Railway stations, banks and other structures from that era were made of limestone in some areas. It is used as a façade on some skyscrapers, but only in thin plates for covering, rather than solid blocks. In the United States, Indiana, most notably the Bloomington area, has long been a source of high-quality quarried limestone, called Indiana limestone. Many famous buildings in London are built from Portland limestone. Houses built in Odesa in Ukraine in the 19th century were mostly constructed from limestone and the extensive remains of the mines now form the Odesa Catacombs.

Limestone was also a very popular building block in the Middle Ages in the areas where it occurred, since it is hard, durable, and commonly occurs in easily accessible surface exposures. Many medieval churches and castles in Europe are made of limestone. Beer stone was a popular kind of limestone for medieval buildings in southern England.

Limestone is the raw material for production of lime, primarily known for treating soils, purifying water and smelting copper. Lime is an important ingredient used in chemical industries. Limestone and (to a lesser extent) marble are reactive to acid solutions, making acid rain a significant problem to the preservation of artifacts made from this stone. Many limestone statues and building surfaces have suffered severe damage due to acid rain. Likewise limestone gravel has been used to protect lakes vulnerable to acid rain, acting as a pH buffering agent. Acid-based cleaning chemicals can also etch limestone, which should only be cleaned with a neutral or mild alkali -based cleaner.

Other uses include:

Many limestone formations are porous and permeable, which makes them important petroleum reservoirs. About 20% of North American hydrocarbon reserves are found in carbonate rock. Carbonate reservoirs are very common in the petroleum-rich Middle East, and carbonate reservoirs hold about a third of all petroleum reserves worldwide. Limestone formations are also common sources of metal ores, because their porosity and permeability, together with their chemical activity, promotes ore deposition in the limestone. The lead - zinc deposits of Missouri and the Northwest Territories are examples of ore deposits hosted in limestone.