Limestone is a common, chemical sedimentary rock formed primarily from calcium carbonate.
It is generally light-colored and can also include fossils of calcium carbonate-containing organisms, like corals.
Limestone can be found all over the world and is the major type of rock found in karst features (crystal cave systems found in bedrock).
Of all the sedimentary rocks found on Earth, almost ten percent of them are some form of limestone. Because it is widely available, it has been used throughout the centuries for many uses, from building materials to chemical additives. Two of the most famous limestone deposits are the islands of the Florida Keys and Niagara Falls.
Properties of Limestone
There are two types of sedimentary rocks: chemical and clastic. Limestone is a chemical sedimentary rock, which forms from the solidification of minerals out of solution into rock form. Because the chemicals in limestone can be readily dissolved by acidic solutions and water, they are able to form karst topography.
Karst topography forms when limestone bedrock chemically reacts with liquids to form unusual features, like stalactites and stalagmites, which are the strange pointy features found in crystal caves around the world and sinkholes. When calcium-rich minerals in limestone are dissolved into groundwater, it forms what is referred to as hard water or water that has higher than normal pH and mineral content.
Depending on the conditions under which they formed, limestone can take on a number of structural shapes, including granular (looking like mineral grains), massive (looking like an irregular blob), crystalline (looking like individual, well-formed crystals), or clastic (looking like fragments of rock). When limestones of any type undergo metamorphism, they re-crystallize as marble. Because all limestone contains calcium carbonate, which reacts with hydrochloric acid to produce bubbles, acid testing is considered one of the most reliable field tests for limestone and calcite mineral identification.
- Polished surface applications
- Hammered surface applications
- Sandblasted surface applications
- Honed surface applications
- Brushed surface applications
- Split Face surface applications