U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2008–3089 

2008

L

imestone, as used by the minerals 

industry, is any rock composed 

mostly of calcium carbonate (CaCO3). 

Although limestone is common in 

many parts of the United States, 

it is critically absent from some. 

Limestone is used to produce Portland 

cement, as aggregate in concrete and 

asphalt, and in an enormous array 

of other products, making it a truly 

versatile commodity. Portland cement 

is essential to the building industry, 

but despite our Nation’s abundance 

of limestone, there have been cement 

shortages in recent years. These have 

been caused in part by a need to find 

new areas suitable for quarrying operations. To help manage our Nation’s 

resources of such essential mineral 

commodities, the U.S. Geological 

Survey (USGS) provides crucial data 

and scientific information to industry, 

policymakers, and the public.

What is Limestone?

“Limestone” means any rock formed 

mostly of calcium carbonate (CaCO3), 

but to geologists, limestone is only one 

of several types of “carbonate rocks.” 

These rocks are composed of more than 

50% carbonate minerals, generally the 

minerals calcite (pure CaCO3) or dolomite (calcium-magnesium carbonate, 

CaMg[CO3]2) or both.

Most carbonate rocks were deposited 

from seawater. These sedimentary carbonate rocks are common on every continent and have formed through most of 

geologic history; they are still forming 

today in the tropics as coral reefs and 

at the bottoms of shallow seas. Marine 

limestone forms because seawater has 

high concentrations of two key dissolved 

chemicals—calcium (Ca++) and bicarbonate (HCO3

–

) ions. In the near-surface 

layer of most oceans, corals, clams, and 

Earth’s surface. This process is called 

“metamorphism.” There are also rare 

“igneous” carbonate rocks that have 

crystallized from molten magma in the 

same way that lavas or granites have. 

These are called “carbonatites,” and this 

rock type is mined at a few places in the 

world as industrial limestone.

Sedimentary limestone deposits 

can be extensive, covering hundreds 

of square miles, and can be relatively 

uniform in thickness and quality. Therefore, limestone quarries can be large 

and long lived, mining limestone layers 

that can be hundreds of feet thick over 

areas of several square miles. Many 

quarries produce multiple products, and 

crushed rocks that are not pure enough 

for certain uses may still be suitable as 

road aggregate. Marble quarries can 

also be very large. However, these rocks 

that were once regularly bedded have 

been metamorphosed into irregularly 

shaped bodies that are more difficult 

and costly to mine.

Limestone—A Crucial and Versatile Industrial Mineral Commodity

other sea-dwelling creatures use these 

two chemicals to make protective shells 

by combining them to form calcite or 

“aragonite,” which is the same chemical 

composition as calcite but has a different 

crystal form.

Some limestones have been changed 

by the introduction of magnesium in 

ground water. Magnesium in ground 

water may convert some or all of the calcite in the limestone to dolomite. Also, 

some rocks formed near the shores of 

ancient seas in arid climates were mostly 

dolomite at the time they were deposited.

Limestone comes in many different 

varieties. Chalk is a very fine grained, 

porous marine limestone composed 

almost entirely of microscopic fossils. 

Travertine is a freshwater sedimentary 

limestone that has very thin, crenulated layers and is commonly formed 

at springs. Marble is a carbonate rock, 

usually a marine limestone, that has been 

squeezed and deformed like plastic by 

great heat and pressure deep beneath the 

Limestone is an essential mineral commodity of national importance. Some of the many products made using limestone are shown in this photograph—breakfast cereal, paint, calcium 

supplement pills, a marble tabletop, antacid tablets, high-quality paper, white roofing granules, and Portland cement. (USGS photograph; use of trade, firm, or product names is for 

descriptive purposes only and does not imply endorsement by the U.S. Government.)
0

0 1,000 feet

400 meters

N

In large parts of the United States 

there are extensive deposits of marine 

limestone of various ages from a few 

thousand to more than 350 million years 

old. Some deposits have chemical grades 

as high as 95% CaCO3. However, some 

areas are completely without any suitable 

limestone deposits. Most of the cost of 

limestone to the customer is determined 

by how far away it comes from and how 

it is shipped. Shipping by barge on water 

is cheaper than by train which, in turn, is 

cheaper than shipping by truck.

Uses of Limestone

Limestone has many industrial uses 

and can be used as mined or processed 

into a wide variety of products. It is the 

raw material for a large variety of construction, agricultural, environmental, 

and industrial materials.

Limestone is used in construction 

almost everywhere. In 2007, crushed 

limestone was 68% of all crushed rock 

produced in the United States. Also, 

limestone is the key ingredient in making 

Portland cement. Despite our Nation’s 

abundance of limestone, there have been 

cement shortages in recent years. 

Some of the purest of natural limestones are marbles. For centuries, marble 

has been the decorative stone of choice in 

government buildings and public statues. 

Travertine is also used as a dimension 

stone in tiles and tabletops. Some white 

limestone is simply crushed and sieved 

for use in landscaping and roofing. 

Powdered limestone is used to remove 

impurities from molten metals like steel. 

It can also remove toxic compounds from 

the exhaust of coal-burning power plants. 

Limestone is used as a filler in a variety 

of products, including paper, plastic, and 

paint. The purest limestone is even used 

in foods and medicines such as breakfast 

cereals and calcium pills.

Limestone is also the raw material for 

making lime (CaO) that is used to treat 

soils, purify water, and smelt copper. 

Lime has many additional uses in the 

chemical industries.

Dolomites are commonly less suitable 

than other industrial limestones for most 

applications. Most dolomite that is mined 

is simply crushed and sieved for use as 

aggregate in concrete or asphalt.

The Portland Cement Shortage

Portland cement is one of the most 

important products made from limestone. 

It is essential in many construction applications. The United States is not self-sufficient in cement and must import it from 

other countries to make up for shortfalls. 

Imports of clinker (the product from the 

first step in making cement) and finished 

cement accounted for about 23% of total 

U.S. cement sales in 2006. In the years 

just prior to 2007, Portland cement was 

in seriously short supply in the Nation. 

Competition from other countries, an 

inadequate ocean transport system, and 

underestimated cargo space requirements 

were among the causes. 

When Portland cement was in very 

short supply, its price increased significantly. Consumers sought substitutes. 

They used pressure-treated wood, insulated steel, and polystyrene in panels, 

and even redesigned building footers to 

reduce the amount of cement needed. 

Cement shortages also caused construction delays that resulted in increased 

costs for roads, bridges, and buildings. 

Sources of Limestone in the Future

Establishing new limestone quarries 

and cement plants in the United States 

Many buildings in the Nation’s capital are 

covered with limestone. The Apex Building/

Federal Trade Commission has an upper exterior of Indiana limestone. (USGS photograph)

DISTANCE TO MARKETS AND SUITABLE QUARRY SITES AFFECT THE PRICE AND AVAILABILITY OF LIMESTONE

In large parts of the United States there 

are extensive deposits of marine limestone. Most of the cost of limestone to 

the customer is determined by how far 

away it comes from and how it is shipped. 

This aerial photograph shows the Antire 

Quarry in a rural setting near Eureka, 

Missouri. Interstate Highway 44 and the 

Burlington Northern and Sante Fe Railroad are at the top right of the photo. The 

quarry is 25 miles southwest of central St. 

Louis, providing easy access to low-cost 

transportation and proximity to major 

markets. Other suitable quarry sites have 

been swallowed up by the city’s growth 

in recent years, resulting in “resource 

sterilization.” (Photograph from GoogleEarth; used by permission of Bussen 

Quarries, Inc.)
is a slow process, and supply shortfalls 

require time to correct. It takes about 2 

years to build a new cement plant, and 

the permitting process can take much longer—8 to 10 years. Perhaps an even more 

challenging problem is that people may 

not welcome new quarries and plants 

to their area. In spite of these obstacles, 

many U.S. cement companies are in the 

process of expanding and modernizing 

their operations.

When an area of suitable and mineable rock is swallowed up by urban 

growth or when mining becomes prohibited by legislation or zoning, the result is 

called “resource sterilization.” Limestone 

is a material of national importance, 

and resource sterilization can result in a 

longer haul at a higher cost from quarry 

to customer.

Limestone Production Patterns

Most of the limestone that is mined 

is crushed for aggregate. The majority of 

U.S. crushed stone production has come 

from limestone for at least the last 40 

years. This is true even though carbonate 

rocks are only 25 to 35% of the rocks at 

the surface. 

U.S. crushed stone operations have 

been declining in number, about 20% loss 

per decade since 1971. However, from 

2001 through 2006, total annual U.S. limestone production increased according to 

U.S. Geological Survey (USGS) Mineral 

Commodity Summaries, so the average 

size of a quarry is increasing. In other 

parts of the world, new production is coming mainly from a few very large quarries. Despite increased U.S. production, 

the Nation was importing more and more 

of its limestone products until the recent 

downturn in construction. These imports 

come primarily from Canada, Mexico, and 

China. With fewer quarries the average 

haul distance will increase, and limestone 

prices will likely increase once more.

Some Issues in Limestone Mining

Limestone is most often mined from a 

quarry. However, underground limestone 

mines are found at places in the central and 

eastern United States, especially in and 

near cities. Underground mining of limestone has some advantages over surface 

quarrying and will probably increase in the 

future. Typical public concerns about limestone mining include dust, noise, blasting 

vibration, and truck and other traffic associated with quarry operations. 

Some limestones are also aquifers, 

that is, they are rock units that can yield 

water to wells. Where limestone is an 

aquifer, there can be concerns that contaminants from the quarrying operations 

could escape into the ground water. 

In many areas of the United States 

where limestone is found, it gradually 

dissolves in rainwater at the surface or in 

the near-surface ground water. In humid 

climates, great volumes of limestone dissolve and are carried away in the water. 

This creates caves, and sinkholes may 

develop where cave ceilings collapse. In 

cavernous limestone aquifers, contaminants in ground water move much faster 

than in other types of rocks, so quarries in 

such areas are special concerns.

The Need to Understand an 

Essential Resource

Limestone is among our Nation’s most 

essential resources. Our understanding of 

that resource as an industrial mineral is 

poor given its importance to our economy. 

Because limestone has been regarded as a 

“common” rock, earlier geologic research 

Great volumes of limestone can be dissolved and carried away by surface and 

ground water. This creates caves, such as Carlsbad Caverns in New Mexico (photo 

at right). In humid climates, cave formation is especially common, and sinkholes may 

develop where cave ceilings collapse. A sinkhole about 240 feet across at ground 

level opened in 1981 in Winter Park, Florida, when the ceiling of an underlying limestone cave collapsed (photo below). The cave and sinkhole are in the Cypresshead 

Formation, which is an important aquifer in central Florida. In cavernous limestone 

aquifers, contaminants in ground water move much faster than in other types of 

rocks, so quarries in such areas are special concerns. (USGS photograph)

DISSOLUTION OF LIMESTONE CAN CREATE CAVES AND SINKHOLES

Stalactites hang from the ceiling, 

and stalagmites rise from the floor 

of Carlsbad Caverns, New Mexico, 

within 260 million-year-old limestone. 

(National Park Service photograph)
trial limestone and limestone products, 

valued at about $2.2 billion. Most of these 

imports were Portland cement. 

Meeting the challenge of supplying 

America’s needs for essential mineral 

commodities such as industrial limestone 

requires accurate and unbiased scientific 

data. The ongoing work of scientists with 

the USGS Mineral Resources Program 

provides the information crucial to the creation of sound policies that will help ensure 

future supplies of mineral resources.

James D. Bliss, Timothy S. Hayes,

and Greta J. Orris

Edited by James W. Hendley II

Layout by David R. Jones

was limited in scope. In the past, 

most USGS research on limestone has 

focused on mapping deposits, as well 

as understanding their roles as aquifers 

and petroleum reservoirs. However, 

different data are needed to characterize limestone suitable for construction 

and other industries. Carbonate rocks 

need to meet chemical purity requirements that vary by intended use. Some 

uses require that the limestone also has 

certain favorable engineering properties. Standards and requirements for 

limestone use are rising, and a greater 

understanding of limestone characteristics, variability, and engineering properties is needed.

Some limestones in the United Sates 

that are otherwise suitable for mining 

and use, such as limestones in many 

parts of Alaska, are currently too distant from markets to be profitable. It is 

important, though, to catalog such rocks 

as possible future resources.

U.S. Industrial Consumption of 

Limestone

Both geologic and economic limits 

will certainly affect future supplies of 

limestone. The United States presently 

consumes between 5 and 10% of the 

global production of industrial limestone. 

In 2007, domestic production of industrial limestone was about 1.3 billion metric tons, valued at more than $25 billion. 

In the same year, the Nation imported 

about 430,000 metric tons of indusAdditional Information

Boynton, R.S., 1980, Chemistry and technology of lime and limestone: New York, 

Wiley, 578 p.

Harben, P.W., 1999, The industrial minerals 

handybook: Surrey, U.K., Industrial Minerals Information Ltd., 296 p.

Harben, P.W., and Kuzvart, M., 1996, Industrial 

minerals—a global geology: London, U.K., 

Industrial Minerals Information Plc., 476 p. 

Kogel, J.E., Trivedi, N.C., Barker, J.M., and 

Krukowski, S.T., eds., 2006, Industrial 

minerals and rocks, 7th ed.: Littleton, Colorado, Society for Mining, Metallurgy, and 

Exploration, 1548 p.

van Oss, H.G., 2008, Cement: U.S. Geological 

Survey Mineral Commodity Summaries, 2 p. 

[http://minerals.usgs.gov/minerals/pubs/commodity/cement/; accessed March 13, 2008]

For more information on industrial limestone and its many uses, please contact the 

following USGS Commodity Specialists: 

STONE—CRUSHED 

Jason Christopher Willett

Phone: (703)-648-6473

Fax: (703)-648-7757

Email: jwillett@usgs.gov

STONE—CRUSHED, AND LIMESTONE

Hendrik van Oss and 

Valentin Trepordi (emeritus)

Phone: (703)-648-7712

Fax: (703)-648-7757

Email: hvanoss@usgs.gov and

 vteporde@usgs.gov

STONE—DIMENSION 

Thomas Dolley

Phone: (703)-648-7710

Fax: (703)-648-7757

Email: tdolley@usgs.gov 

LIME

M. Michael Miller

Phone: (703)-648-7716 

Fax: (703)-648-7757

Email: mmiller1@usgs.gov 

Additional information is available from the 

following USGS Mineral resource specialist:

STONE—DIMENSION AND CRUSHED

William H. Langer 

U.S. Geological Survey 

Box 25046, Mail Stop 964

Denver Federal Center

Denver, CO 80225

Phone (303) 236-1249

Email: blanger@usgs.gov

Other sources of information:

USGS Mineral Resources Program

 http://minerals.usgs.gov/

Lime

 http://minerals.usgs.gov/minerals/pubs/ 

 commodity/lime/

Cement

 http://minerals.usgs.gov/minerals/pubs/

 commodity/cement/

Crushed stone

 http://minerals.usgs.gov/minerals/pubs/

 commodity/stone_crushed/

This Fact Sheet and any updates to it are 

available online at http://pubs.usgs.gov/

fs/2008/3089/.

Limestone quarry in Florida (USGS photograph)