Limestone

What is limestone? Limestone is sedimentary rock formed from the shells of organisms. It is composed mostly of calcite (calcium carbonate CaCO3 Carbonate Group, hardness 3; specific gravity 2.7), a soft mineral which is soluble in acid. A closely related mineral, dolomite, Calcium Magnesium Carbonate (MgCaCO3 Carbonate Group; hardness 3-5.4, specific gravity 2.86) is often found mixed with limestone.
Where crushed stone is quarried

Where are they found geographically? Limestone is found throughout all of middle Tennessee and scattered through east Tennessee.
When were they deposited? Limestone is deposited only in warm shallow oceans. It was deposited in Tennessee throughout the Paleozoic Era (570-251 million years ago). The limestone which is used commercially was deposited during the Ordovician Period.

School science's web page on analyzing limestone.
Quaternary
Tertiary
Cretaceous
Jurassic
Triassic
Permian
Pennsylvanian
Mississippian
Devonian
Silurian
Ordovician
Cambrian
Proterozoic

Middle Tennessee is dotted with abandoned limestone quarries, like this one in Murfreesboro.

 How were they collected and used? Limestone is quarried from open pit mines. During the 19th century, large numbers of small limestone quarries were scattered across eastern and middle Tennessee. More recently, the many small quarries have been replaced by a few large ones.
History of the use of limestone in Tennessee Limestone has been used in many different ways.
  • In the 18th and 19th centuries, limestone was used as a building stone. In Nashville, all of the early government buildings were built of locally quarried limestone. By this century, the use of so called dimension limestone has been replaced in construction by cement.
  • In the iron mining regions of west Tennessee, limestone was quarried for use in smelting.
  • Middle Tennessee limestone has been used as an artistic medium. The early 20th century sculptor, William Edmondson is the most famous sculptor to work in Tennessee limestone.
  • Limestone is still quarried in middle Tennessee but now it is crushed and used as crushed rock or to make cement or use as an agricultural chemical (to neutralize acid soil).
  • The very pure dolomite of the Ordovician Holston Formation, quarried in east Tennessee is polished and sold as decorative rock under the name Tennessee marble. Look for Pink Tennessee Marble at the Lincoln Memorial, Thomas Jefferson Memorial, and the National Gallery of Art.

The Tennessee State Capitol was built from limestone from the Nashville Basin

Limestone is a more convenient building material when used as cement.

 Uses of Limestone With the exception of Tennessee "marble", limestone is not used as building stone any more. The two major uses of limestone are as the major ingredient in cement, and an agricultural additive, used to reduce the acidity of soil.
Environmental consequences of limestone mining. While limestone is being quarried it creates noise and truck traffic and raises dust. After the quarrying is completed quarries are left as great holes in the ground. Other than that, limestone quarrying poses few environmental hazards This abandoned limestone quarry in Wilson County is used to train scuba divers, who explore the abandoned mining equipment at the lake bottom.