Limestone is lauded for its lasting durability and versatility. Maintaining an enduring material history, the nuanced natural stone has been utilized for millenniums in the making of many architectural masterpieces. Storied limestone structures situated around the world have stood the test of time, demonstrating the distinct advantages achieved with its application. Continuing to play a critical role in contemporary design and architecture, limestone’s many applications include facades, flooring, landscaping, coping, and paving, among others. The information that follows explores the historical uses, physical properties, visual varieties of limestone.
Limestone holds a long legacy of use as an architectural material, appearing across an array of ancient edifices throughout history. Built to stand the test of time, the earliest uses of limestone can be traced back to ancient Egypt and Greece. Included in the comprehensive catalog of architectural creations constructed out of limestone are the Great Pyramid of Giza and the Sphinx, as well as the carefully constructed columns of the Parthenon. “Limestone has a great history in architecture because it’s such a widely accepted building material,” says Mike Buechel, COO of Buechel Stone.
Natural Indiana limestone was used in the construction of the Lincoln Memorial and the Empire State Building, as well as in the reconstruction of the Pentagon. “When people think of limestone, more often then not they think Indiana limestone, and for good reason,” adds Buechel. “It is probably one of the oldest commercially marketed natural stones for so many reasons. It’s versatile enough to be used for veneer, carving, and paving purposes. It is monolithic, so you know what you are going to get. And it is located centrally in the United States to ship anywhere easily, especially early on in American history. That brings us to today, where people are starting to understand that there’s a wide range of options for limestone.”
Limestone is a type of sedimentary flagstone that originates under the earth’s oceans. Created through natural processes, limestone is formed when layers of minerals combine with sediment and shells of marine organisms and undergo lithification. Limestone is later dug up in large quarries, which are located predominantly in the Midwest within Unites States. The stone’s chalky and powdery properties come from its calcium carbonate composition, which also makes it malleable and ideal for carving. However, the softness of limestone is balanced by its resilience and strength. Since the stone is formed from a rigorous process that plays out underground, it is inherently able to withstand a lot of pressure and wear-and-tear.
With drastic differences in density, hardness, and porosity, an especially extensive range of limestone varieties exists. “People often hear ‘limestone’ and think of a soft stone,” says Buechel. “That is really just a small part of the overall range of limestone. From a testing standpoint, ASTM classifies limestone in three categories: Type I, Type II, and Type III. Type I is the softest and has to have a minimum density of 110 pounds per cubic foot, and an absorption rate max of 12 percent. Type II is at least 135 pounds per cubic foot, and an absorption rate max of 7.50 percent. Last is Type III, with a minimum density of 160 pounds per cubic foot, and absorption rate of three percent or less.” Thus, the category of limestone is comprehensive with a broad scope of classifications. “Limestone’s wide range of physical properties have often made it misunderstood,” adds Buechel. “But in reality, this is really what makes limestone such a great product. You can get a stone that’s soft, almost delicate, or a stone that’s hard, dense, and able to withstand the worst conditions that mother nature can throw at it.”
The latitude of limestone variations extends to its visual qualities as well. Depending on where it has been harvested, color variations can further distinguish varieties of limestone. From traditional buff or beige tones to tawny blush or pink casts, many color distinctions can be found, and finishes can be combined to create deeper and more dramatic hues. “Limestone is often considered very monolithic, and that is just not the case for all limestones,” says Buechel. “Our Chilton limestone is a very dense, Type III Limestone, with more color variation than almost any other stone I’ve seen. It can range from cool grays, buffs, and charcoals to reds, mauves, and mottled blues.”
Offered in a range of finishes—from sleek and polished to a more tactile hammered texture—limestone lends itself to many design aesthetics. In addition to the application approach utilized, limestone’s visual versatility can be further adapted with hand carvings, custom moldings, and other decorative designs that can complement a range of rich materials. “A layered limestone allows you to install the stone in a wide range of visual appearances from mosaic, ashlar, or contemporary looks with precise sawn heights,” says Buechel. “Large blocks of limestone are common from Indiana, our own Silverdale, Aged Parchment and Harvest Straw, can be shaped and cut into detailed work such as columns and balusters, window surrounds, and sills, and you can also make panels for a veneer. Really, your options are pretty much open.” Limestone’s subtle variations and seemingly ceaseless array of aesthetic adaptations serve to supply a diverse selection of enduring design possibilities.