Limestone is a sedimentary rock. It's mainly composed of calcium carbonate (CaCO3) in the form of calcite, and is mostly organic. It forms commonly in shallow, clear, warm marine waters. The rock forms from the buildup and collection of coral, shell, fecal and algal debris. It can also be a chemical sedimentary rock created by precipitation CaCO3 from ocean or lake waters.
How Limestone is Made
Limestone starts out as dead shells and organisms that have fallen to the bottom of the ocean or a body of water. Over millions of years of heat, pressure, and more sediment gathering, the heat and pressure compacts the shells and sediment into limestone (CaCO3). It is then mined in quarries by machines. If heated in a rotary kiln, the limestone becomes what is called quicklime (CaO). If water is added to the quicklime, it becomes slaked lime (Ca(OH)2). Then, the slaked lime is carbonated ( by adding CO2), and is becomes limestone again!
Save the Limestone!
Although limestone can be industrially made, it is still considered a nonrenewable resource, meaning that it is being used up faster than it can be naturally replaced. If it were renewable, it would easily be replaced in a short matter of time, like trees. Since we are using it up so quickly, we should try to preserve it, so that it doesn't disappear. Even though it's industrially made, it's still not even near having the qualities of an inexhaustable resource, which is never depleting, like solar energy, or wind.
Advantages of Quarries
The advantages of mining quarries are that the quarry, once all the limestone is extracted, can be filled with water to become a lake, pond, or even a river. These can be used for fishing and water sports, and may even attract people. The quarries may also attract locals to work in the quarry, giving more job opportunities to locals.