Limestone is a sedimentary rock made up of mostly calcium carbonate, although it can contain small amounts of other minerals such as quartz or feldspar. There are many different forms of limestone, but they all have at least 50% calcium carbonate. Limestone has widespread uses today, and there is evidence that it was even used by early humans as much as 14,000 years ago as an ancient motor. Limestone such as chalk commonly forms in shallow seas and where coral reefs thrive. Indeed, many forms of limestone are made up of tiny fragments of the shells of sea creatures. Fossils of these creatures are common in marine limestone. There are still places on earth where this type of limestone is still being formed today. Limestone can also form through evaporation in stalactites and stalagmites or near hot springs or lake shores.

Limestone in daily life

The extent and variety to which we utilize limestone is great. Its industrial applications include the use in a number of construction materials, both directly as cut stone and with other minerals such as in cement. It’s also used in the production process for steel and for purifying waste water.

Our homes are filled with limestone from paper and glossy magazines to impact resistant plastic, even in many toothpastes. Nearly one third of glass is made up of limestone, and lime is used to absorb impurities in sugar during processing. Additionally, we have lime to thank for the foods we consume. It’s an effective product for reducing acidity and releasing nutrients for plant use in gran and vegetable fields. The cows who produce our milk need lime in their feed so they have enough calcium in their diets, and the chickens who lay our eggs need it to produce strong shells.