Indiana Limestone
by:
John R. Hill
Indiana Limestone, which is a Mississippian-age grainstone of very uniform texture and
grade, has gained world-wide acceptance as a premier dimension stone. The Salem
Limestone, which is the geologic formational name for this carbonate unit, crops out in a belt
that trends southward from Stinesville in Monroe County to Bedford in Lawrence County. The
outcrop belt varies in width from about a mile to nearly 10 miles near Bedford.
Blocks of limestone being sawed to size.
The earliest known Indiana Limestone quarry was opened southeast of Stinesville in 1827 by
Richard Gilbert. In 1928, the zenith of American-stone architecture, Indiana furnished 14.5
million cubic feet of dimension stone. At present, nine quarries extract the Salem Limestone. Most of the quarries use modern diamond belt saws to dimension the quarry
blocks and air bags to turn down the cuts. Individual quarry blocks are broken using the time-honored method of driving steel wedges between half-shell slips or feathers
that are placed in holes drilled by pneumatic star bits.
Indiana Limestone is a freestone, which means that it exhibits no
preferential direction of splitting and can, therefore, be cut and carved
in an almost limitless variety of shapes and sizes. This property allows
the stone to be planed, turned on a lathe, sawed, and hand worked to
match the requirements of the most demanding architectural designs.
Indiana Limestone exhibits three colors: gray, buff, and variegated,
which includes patterns of both gray and buff.
Did you know:
That nearly 2.7 million cubic feet of Indiana Limestone is quarried
each year?
That, although a relatively small industry, the Indiana Limestone
industry generates about $26 million annually in revenue?
That Indiana Limestone can be quarried and milled with greater
efficiency, in terms of energy consumed, than most competing
building materials?
The Empire State Building in New York City is clad in Indiana Limestone.
That Indiana Limestone has stood the test of time in structures all
over the world where its strength, beauty, and durability have made it the material of choice in many older load-bearing structures as well as cladding stone in the
modern context?
That the Indiana Limestone industry employs stone cutters and carvers whose skills in working limestone into complex shapes and into art forms remain world class?
Performance
To those interested in the performance of Indiana Limestone as a building material, the following information will be of interest:
PROPERTY
VALUE
TEST PROCEDURE
Ultimate compressive strength of dry specimens
4,000 psi minimum*
ASTM C170
Modulus of rupture of dry specimens
700 psi minimum**
ASTM C99
Absorption
7.5 percent maximum
ASTM C97
*Compressive-strength values of most Indiana
Limestone products indicate minimum values in
excess of 4,000 psi, but this value is listed as an
engineering reference.
**Windload and other bending forces are typically
calculated at 1,000 psi for modulus of rupture.
Beautiful Indiana Limestone adorns the U.S. Holocaust Memorial and Museum in Washington, D.C.
Indiana Limestone is chemically pure, averaging 97 percent plus calcium carbonate and 1.2 percent calcium-magnesium carbonate, thus qualifying the material as a
chemical stone.
For more information on Indiana Limestone, contact the Mineral Resources Section of the Indiana Geological Survey at 812-855-2687, or contact the Indiana Limestone
Institute at:
Indiana Limestone Institute of America, Inc.
Indiana Limestone Institute of America, Inc.
Suite 400
Stone City Bank Building
Bedford, IN 47421
(812) 275-4426
Web site: http://www.ILIAI.com/