Per diem localities with county definitions shall include "all locations within, or entirely surrounded by, the corporate limits of the key city as well as the boundaries of the listed counties, including independent entities located within the boundaries of the key city and the listed counties unless otherwise listed separately. Introduction Limestone is a sedimentary rock composed principally of calcium carbonate calcite or the double carbonate of calcium and magnesium dolomite.
Some calcarenites contain oolites and if the oolites are present in sufficient quantity, the stone is called oolite limestone. Oolite limestone is a sub-category of calcarenite. Coquina:Coquina consists of raw, unaltered shell fragments, often quite large, loosely cemented by calcite.
It is generally very coarse and porous, frequently consisting of oyster and sea shells and fragments. Dolomite: Dolomite is a sedimentary carbonate rock composed of calcium and magnesium carbonate. Microcrystalline limestone: This is a limestone structure of crystals too small to be seen without magnification. Oolitic limestone: Oolitic limestone is a calcite cemented calcareous stone composed of shell fragments, practically non- crystalline in character. Generally without cleavage, and extremely uniform in composition and texture, oolitic limestone adjusts to temperature changes.
Travertine:A calcium carbonate, usually light in color, travertine can be extremely porous or cellular. It is usually deposited from solids in groundwater. Typical Uses Limestone is widely used in architectural applications for walls, decorative trim and veneer. Problems and Deterioration Weathering may have a degrading effect on the appearance and structural soundness of limestone.
Natural or Inherent Limestone Problems Weathering: Limestone subjected to exterior exposures deteriorates due to weathering or the natural effects of wind, rain, and thermal change. Erosion: Erosion can be the result of general weathering described above, or it can be a more localized phenomenon based upon handling or exposure. Staining: Discoloration of the limestone, whether general or localized, is staining. A variety of organic or inorganic oils may be absorbed into the stone upon contact.
Dyes and inks: The staining could be any color depending on the type and source of the dye. This type of stain is likely to be extremely localized around the area of contact. The liquid containing the coloration may be absorbed into the stone and during the normal process of evaporation, the coloring pigment is deposited in the stone.
For specific guidance on removing ink and dye stains from limestone, see R. Organic stains: Organic stains are caused by direct contact with decomposing organic matter, such as leaves, bird or animal droppings, flowers, tea or coffee.
Regardless of the source these stains tend to be a slight reddish-brown in color. They also frequently disappear after the source has been removed. These stains may be left to weather and bleach or oxidize out after the removal of the organic source, however a residue may still remain on the stone. For specific guidance on removing organic stains from limestone, see R. Metallic stains: Two major categories of metallic staining occur, they tend to be based on either iron or copper. The source of the staining may be internal structural components or elements.
A major source is the water wash, or run-off, from adjacent metallic elements, especially bronze and copper. Rust stains: These stains are reddish-orange and are caused by the oxidation rusting of iron. The source of iron staining is usually the structural or connecting components. These components are usually hidden and protected; however, water penetration from bad joints or cracks can activate or accelerate rusting.
The discoloration may be within the stone or it may be a deposit of rust on the surface of the stone. Surface deposits of rust may sometimes be removed by hand rubbing with a clean cloth. The examination of the stain should include such rubbing to determine if it is only a surface deposit. For specific guidance on removing rust stains from limestone, see R.
Bronze and Copper stains: Stains from water run-off from bronze can range in color from a light green to a dark brown.
The staining results from the dissolved copper salts from copper or bronze which wash onto the stone, then oxidize. The pattern of the staining is likely to be localized, streaked and in the path of the run-off from the metallic source.
For specific guidance on removing bronze and copper stains from limestone, see R. Crumbling: This condition is indicative of a certain brittleness or tendency of the stone to break up or dissolve. Chipping: The separation of small pieces or larger fragments from a masonry unit, frequently at the corners, edges or mortar joints is known as chipping. Detachment: This is not a failure of the material per se but a failure of the construction system, i. Efflorescence: The appearance of a whitish deposit locally or uniformly over the surface may be efflorescence, the surface deposition of soluble salts.
Erosion: Erosion is the wearing away of the material surface by the natural action of wind, windblown particles and water. Flaking: This is an early stage of peeling, exfoliation, delamination or spalling evidenced by the detachment of small flat thin pieces of the outer layers of stone from a larger piece of stone.
Peeling: Peeling is the flaking away of the stone surface from the substrate in strips or layers. Rising Damp: Rising damp is the suction of ground water into the base of masonry through capillary action.
Spalling: Spalling is the separation and breaking away of pieces of stone due to sub-florescence, freeze-thaw, improper repointing withtoo hard a mortar mixcontaining too much portland cement, or structural overloading of the stone.
For specific guidance on repairing spalling limestone, see R and R. Sub-florescence: This is a potentially harmful internal accumulation of soluble salts deposited under or just beneath the masonry surface as moisture in the wall evaporates. Last Reviewed: Get my location Current location OR.
City optional. Here stalactites, stalagmites, and flowstone adorn the roof, floor, and walls of the cave. These rocks are a variety of limestone known as travertine.
Limestone can also form through evaporation. Stalactites, stalagmites, and other cave formations often called "speleothems" are examples of limestone that formed through evaporation. In a cave, droplets of water seeping down from above enter the cave through fractures or other pore spaces in the cave ceiling.
There they might evaporate before falling to the cave floor. When the water evaporates, any calcium carbonate that was dissolved in the water will be deposited. Over time, this evaporative process can result in an accumulation of icicle-shaped calcium carbonate on the cave ceiling. These features are known as stalactites. If droplets fall to the floor and evaporate there, stalagmites could eventually grow upwards from the cave floor.
The limestone that makes up these cave formations is known as "travertine," a chemical sedimentary rock. A rock known as "tufa" is a limestone formed by evaporation at a hot spring or on the shoreline of a lake in an arid area. All limestones contain at least a few percent other materials.
These can be small particles of quartz , feldspar , or clay minerals delivered to the site by streams, currents and wave action. Particles of chert , pyrite , siderite, and other minerals can form in the limestone by chemical processes. See our article about the " acid test " for identifying carbonate rocks and minerals. There are many different types of limestone - each with its own name. These names are often based upon how the rock formed, its appearance, its composition, or its physical properties.
Here are some of the more commonly encountered types of limestone. Chalk: A fine-grained, light-colored limestone formed from the calcium carbonate skeletal remains of microscopic marine organisms.
Chalk is the name of a limestone that forms from an accumulation of calcareous shell remains of microscopic marine organisms such as foraminifera. It can also form from the calcareous remains of some marine algae. Chalk is a friable limestone with a very fine texture, and it is easily crushed or crumbled. It is usually white or light gray in color.
In the past pieces of natural chalk were used to write on blackboards. Today, most blackboard chalk is a man-made product. Some of it is made from natural chalk along with additives that improve its performance. Coquina: This photo shows the shell hash known as coquina. The rock shown here is about two inches five centimeters across. A small amount of calcareous cement usually binds the grains together.
The sediments that form coquina accumulate on beaches where wave action delivers an abundance of locally produced biological grains, while a significant amount of other material is not deposited. Coquina might be composed of mollusk, gastropod, brachiopod, trilobite, coral, ostracod or other invertebrate remains.
See accompanying photo or read an entire article about coquina here. Crystalline Limestone: A specimen of limestone that has been subjected to metamorphism. Some might call this material "crystalline limestone" - however, the proper name is marble. If you view this rock closely by eye, or better, with a hand lens, you will clearly see cleavage faces of calcite intersecting at rhombic angles.
The rock shown here is about four inches ten centimeters across. When limestone is subjected to heat, pressure, and chemical activity, the calcite in the rock begins to transform. This is the beginning of the process known as metamorphism. Starting at a microscopic scale, the calcium carbonate in the rock begins to crystallize or recrystallize into fine-grained calcite crystals.
As the duration and intensity of metamorphism continues, the calcite crystals increase in size. When the calcite crystals are large enough to be visible to the eye, the rock can then be recognized as marble - a metamorphic rock. Marble is the name of the metamorphic rock that forms when limestone is subjected to the heat and pressure of metamorphism. It is composed of calcium carbonate CaCO 3 and usually contains other minerals that might include clay minerals, micas, quartz, pyrite, iron oxide, and graphite.
At this location, and many other locations, the Kaibab Limestone is fossiliferous and dolomitic. Photograph by the United States Geological Survey. Dolomitic limestone is a rock composed mainly of calcite, but some of that calcite has been altered to dolomite. Dolomite is thought to form when the calcite CaCO 3 in carbonate sediments or in limestone is modified by magnesium-rich groundwater. The available magnesium facilitates the conversion of calcite into dolomite CaMg CO 3 2.
This chemical change is known as "dolomitization. Dolomitization can completely alter a limestone into a dolomite, or it can partially alter the rock to form a "dolomitic limestone. Fossiliferous Limestone: Ammonite fossils found in limestone quarry in Germany. Ammonite fossils are abundant in the area around Nuremberg and Stuttgart.
Fossiliferous limestone is a limestone that contains obvious and abundant fossils. They are usually marine invertebrates such as brachiopods, crinoids, mollusks, gastropods, and coral. These are the normal shell and skeletal fossils found in many types of limestone.
Fossiliferous limestone often contains information about the environment of deposition, and where the organisms lived or were deposited. Paleontologists can often examine the fossils and determine the geologic age of the rock. Lithographic Limestone: In , workers at NOAA's printing shop ink a slab of lithographic limestone that contains an image of a nautical chart. Oolitic Limestone is composed of calcium carbonate oolites, which are tiny grains that are composed of concentric layers.
Limestone is often used as a material for many home remodeling projects. Below are many great options that you have for your new limestone countertops, backsplashes, vanity tops or other home surfaces. Ataija Creme is a tan colored stone that has strong hints of grey.
Its beautiful weathered appearance will look great in any home. This gorgeous gold Italian limestone is great for any home. If you are looking for a light stone to incorporate in your space, Giallo Reale Limestone is a wonderful choice. This beautiful stone is quarried in Israel and is best for low traffic areas of the home, like the bathroom. Perhaps you consider Jerusalem White Limestone for your new vanity top.
This beautiful grey natural stone is often used for vanity tops, tub surrounds and more. This gorgeous natural stone is quarried in Portugal and is a perfect material to use for home structures in low traffic areas, like the bathroom. Moleanos Limestone is a beautiful beige stone from Portugal. It is a great choice for a bathroom remodel. Whether it is in the home or outside the home, there are many types of limestone that serve many different purposes.
This stone is one of the most common building materials that you will find. Whether it is chalk or your new countertop, examples of the various types of limestone surround us every day. Call now for assistance: Visit our Virtual Yard. Toggle navigation. Contact Us Frequently Asked Questions. Our agents can help you choose a countertop.
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