Indiana Oolitic Limestone: Natural Properties

Indiana Oolitic Limestone has been used for centuries in the construction of buildings and monuments. It is a unique material, distinguishable by its wide variety of colors, calcite streaks and spots, shells and fossils, as well as other features.

As the adage goes ‘form follows function,’ Indiana Limestone is renowned for its structural soundness and versatility in application.

This article will explore the natural properties of this building material and discuss how to identify both color and grade when specifying it.

Key Takeaways

  • Indiana Oolitic Limestone is a popular building material with unique natural features such as calcite streaks or spots, shells, fossils, pit holes, reedy formations, open texture streaks, honeycomb formations, iron spots, travertine-like formations, and grain formation changes.
  • The stone comes in various colors including buff, variegated, and gray, and textures such as machine-tooled, rock face, sandblasted, smooth, split-faced, and tumbled stone.
  • Indiana Limestone Company offers four grades based on granular texture and natural characteristics: Select, Standard, Rustic, and Variegated.
  • To achieve the best possible color match, it is advisable to use stone from a single quarry, and large-scale samples can be helpful in selecting stone color and quality.

What Makes Indiana Oolitic LImestone Unique

Indiana oolitic limestone is unique in its combination of buff and gray colors, varying shades and textures, as well as its distinct natural characteristics such as calcite streaks or spots, fossils or shelly formations, pit holes, reedy formations, open texture streaks, honeycomb formations, iron spots, travertine-like formations, and grain formation changes. Its popularity has made it a building material of choice for many prestigious buildings throughout the state of Indiana such as the Pentagon and Reagan Building.

The stone is graded based on fineness of grain particles and other natural characteristics which include select grade with fine to average-grained texture with minimum unique features; standard grade has fine to moderately large-grained texture with average amount of distinguishing features; rustic grade is fine to very coarse-grained with above-average amount of unique visual elements; and variegated grade composed from unselected mixture of grades 1-3 may appear in both buff and gray colors. In addition to these qualities that make it desirable for construction purposes, Indiana limestone also contains calcium carbonate which makes it an ideal material for most chemical processes.

The stone’s color variations can be further enhanced by applying various surface finishes such as plucked finish which provides smooth surface without visible tool marks; tooled finish gives a uniform appearance but does not provide any texture depth; bushhammer finish produces a rough textured surface using steel bits while crandle finish uses chisels instead; rock face cut gives an uneven look like naturally weathered stone surfaces while split face cut gives a rough but regular patterning when viewed from distance; tumbled process produces rounded edges while shotsawn creates coarse grooves that add permanent brown tones to the stone’s color variations.

In order to ensure best possible match between the sample chosen by designers/specifiers and final building appearance using Indiana limestone stones from single quarry is recommended due to subtle differences in color shade within same sample even though fabricator nor erector will attempt to control location of panels or stones according to natural variations of color or texture.

The “Not-So-Cool” Marks on the Stone

Unappealing markings such as shell holes, ‘glass’ spots, and veins often plague the otherwise pristine surface of Indiana Oolitic Limestone, detracting from its aesthetic appeal. These features are natural occurrences in the stone which form as a result of their long burial under sedimentary deposits and exposure to extreme temperatures over time.

The use of Indiana Oolitic Limestone has been widespread throughout the construction industry since it was discovered in a series of limestone belts running through the state. Despite the presence of these less desirable features, there is still much information to be gathered about this unique material that can help make it work for any project:

  • Types: There are four different grades based on grain size and characteristics; select (fine-grained with minimal natural characteristics), standard (fine to medium-grained with average natural characteristics), rustic (fine to very coarse-grained with above average natural characteristics), and variegated (mixture of grades 1-3).
  • Characteristics: Stones may contain calcite streaks or spots, fossils or shelly formations, pit holes, reedy formations, open texture streaks, honeycomb formations, iron spots, travertine-like formations etc.
  • Location: It is advisable to use stone from a single quarry for color control and best possible color match.
  • Quality: Large scale samples including sample walls can be helpful in selecting stone color and quality. As stone sizes increase grade selectivity decreases.
  • Surface Finish: Designers need to identify both the color and grade required when specifying Indiana Limestone along with the surface finish applied to the stones. Bushhammering is one example which produces a textured surface suitable for exteriors but should be confined only to coarser grains used on flat surfaces.

Indiana Limestone provides an unmatched versatility for architects while offering superior products for many industries around the world due its unique properties and characteristics despite some undesirable marks on its surface.

This knowledge helps designers plan accordingly when considering all aspects necessary in choosing this type of limestone without compromising on quality or appearance thus allowing them to make informed decisions based on their individual needs.

Weathering: How Nature Changes the Stone

Weathering, from the elements and time, can cause changes in the color of stone over time due to its exposure above or below ground-water levels.

Lawrence County is renowned for its abundant Oolitic Limestone deposits; it is a major part of Indiana’s history and culture. Oolitic Limestone consists of oolites that are formed over thousands of years by the accumulation of calcium carbonate around a nucleus such as a grain of sand, shell fragment or fossil.

The Empire Quarry in Bloomington has been supplying quality limestone since 1827 and is one of many quarries in this area. The annual Limestone Fest at Lime Rock Park celebrates both Indiana’s limestone heritage and current industry with events like the Limestone Throwdown rock hauling contest.

The various types of limestone present in Lawrence County include fossiliferous limestone which contains fossils such as brachiopods, corals and crinoids embedded in the matrix along with oncoid formations. It also contains some chert nodules which are cavities filled with quartz crystals which are believed to be formed by ancient bacteria colonies growing on the surface.


Nature has created these unique features within each piece making each block stand out from another whether subtly or substantially in shade and texture adding character to any building design. Due to its hardness, Indiana oolitic limestone stands up well against weathering but still can change over time depending on its environment making it an ideal choice for outdoor projects that won’t require regular maintenance but will last for generations.

Whether used as ashlar masonry or other applications, Indiana oolitic limestone presents an attractive option given its abundance and versatility when compared to other natural stones available today.

The Mysterious “Crowfeet”

The mysterious ‘crowfeet’ or stylolites, jagged surfaces filled with clay or minerals, can give Indiana oolitic limestone a unique appearance. These features are formed naturally in the stone and have various effects on its look.

The size of these features vary from quarry to quarry and can be analyzed through publications available at the Bedford Public Library. The government of the Bedford region has even adopted an Indiana Limestone logo to represent their area.

When investigating crowfeet in Indiana Limestone it is important to note that they appear differently based on their size, shape, and location within the stone. Smaller crowfeet will create a smoother texture while larger ones will be more obvious and pronounced.

Depending on where they are located in relation to other natural features such as calcite streaks or fossils, they can add variation and depth to the overall look of the stone.

Due to its adaptability, Indiana limestone has been used for countless large-scale projects including the Pentagon, Reagan Building, Federal Triangle, Iowa State Capitol, Millennium Park and Schermerhorn Symphony Center. This versatility means that architects can take advantage of this unique material when creating a project tailored to their needs.

Understanding how crowfeet affect the stones appearance is essential for achieving desired results.

When the Stone Breaks: Understanding Fractures

Fractures in Indiana Limestone can cause dramatic changes in color, creating unique patterns that range from subtle to pronounced, depending on the size of the fracture. These fractures occur when certain parts of the stone become weak due to expansion or contraction of certain minerals within it. The fractures are usually caused by a combination of physical and chemical weathering processes such as erosion, abrasion, and dissolution.

As a result, these features are often found in caves, cliffs, waterfalls, sinkholes, gorges and other areas where water is present. Fractures may also be formed by tectonic forces such as seismic activity.

Understanding the characteristics and features of Indiana limestone is essential for architects and engineers who wish to use it in their projects because they must be aware of how these fractures can affect its performance over time. By knowing the rights documents associated with using this material for their projects they can ensure that their structures will remain strong and perform well over time.

Indiana Limestone has many properties which make it a desirable building material but its network of natural fractures needs to be considered before construction begins. When examining a sample of this stone one should look out for signs such as open-bedding planes or calcite streaks which indicate potential fracturing zones that could form when exposed to extreme temperatures or stress levels during construction.

It’s important for architects and engineers to have an understanding not only about how these fractures form but also how they might affect the stability of a structure over time if proper precautions aren’t taken into account during planning stages. Additionally they should consult relevant documents related to using this material so that they understand all rights associated with constructing with Indiana Limestone properly.

With knowledge on these topics one can confidently create beautiful structures made from this versatile stone without worrying about compromising safety or performance standards throughout its lifetime.

Experiments with the Stone

Experiments involving running water over Indiana Oolitic Limestone slabs have been conducted to further understand its properties and interactions with the environment. This type of experiment is especially important for understanding how the stone will react to environmental conditions in places like Bloomington, Salem, and other areas where it is used in various structures such as canyons, valleys, bridges, columns, domes, mountains, hills and ridges.

The results of these experiments show that Indiana Oolitic Limestone has a relatively low resistance to weathering when compared to other stones. It is also highly porous which makes it vulnerable to moisture and susceptible to staining. In addition, it has a tendency to fracture due to its crystalline structure. This makes it prone to cracking if not properly supported or reinforced when used in certain applications. Therefore, proper maintenance and care must be taken when using this stone in order to ensure its longevity.

Indiana Oolitic Limestone also has unique visual features which make it an attractive choice for many projects. Its buff color ranges from light creamy shades to brownish hues while its gray color ranges from light silvery tones to bluish grays with various characteristics such as calcite streaks or spots, fossils or shelly formations, pit holes and reedy formations among others. Additionally, variegated colors are available which contain both buff and gray coloring along with various textures and characteristics making this particular limestone even more versatile than usual.

Due the variety of shapes sizes finishes available for Indiana Oolitic Limestone combined with its unique natural features it can be used in a wide range of applications including walls walkways driveways patios fireplace surrounds outdoor kitchens decks stairs benches columns fountains fire pits etc., making it an ideal building material for many types of projects large or small alike. With proper maintenance and care this durable yet beautiful stone can last several lifetimes ensuring generations of enjoyment for years come.


Indiana Oolitic Limestone is a material with many unique characteristics that make it an ideal building material for a variety of projects. Its color and grade must be considered when specifying the stone, as these features will influence its soundness and durability.

The calcite streaks, spots, shells and fossils all add to the visual appeal of the stone while its weathering ability can give it a vintage look. Lastly, its mysterious crowfeet are not only visually interesting but also help to identify fractures in the stone.

Indiana Oolitic Limestone is truly one-of-a-kind and must be handled with care for optimum results in any project.

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