Limestone has been the material of choice for some of the world’s greatest architecture. From the Great Pyramid in Giza, Egypt, to medieval European churches and castles, to New York’s Empire State Building, limestone stands the test of time. Because it is a fine-grained, soft rock, limestone is easily cut into a variety of shapes and thickness levels, making it an ideal stone for creative architecture.
While there are dozens of varieties of limestone found throughout the world, Indiana Limestone--known by geologists as Salem Limestone--is considered the product of choice for its consistency of deposit. Though it is extremely homogenous, genuine Indiana Limestone has subtle differences in color and grain. Remnants of the past are sometimes visible in small concentrations of calcite streaks or spots, fossils or shell formations, pit holes, reedy formations, open texture streaks, honeycomb formations, iron spots, travertine-like formations, and grain formation changes. Because these variations are so minimal, each piece of stone looks very similar to the next, providing a smooth, uniform look to the architecture.
Indiana Limestone is classified into two colors--Buff and Gray; and four grade descriptions--Select, Standard, Rustic, and Variegated. To ensure optimal color control, the Indiana Limestone Institute of America (link: http://iliai.com/) recommends that stone for each project should be supplied by a single quarry.
Buff: Varies in shades from a light cream to a brownish buff.
Gray: Appears in shades of silvery gray to bluish gray.
Select: Fine to average-grained stone having a controlled minimum of the above characteristics
Standard: Fine to moderately large-grained stone permitting an average amount of the above characteristics
Rustic: Fine to very coarse-grained stone permitting an above-average amount of the above characteristics
Variegated: An unselected mixture of grades 1 through 3 permitting both the buff and gray colors
For more information on Indiana Limestone, including architecture, installation, repair and restoration, view the Indiana Limestone Handbook