Limestone coloration is generally a consistent pure white to off-white.Many varieties do not take a polish well, so that the surface is typically a matte finish, no-gloss surface.Limestones, like marble and other calcareous stones, are referred to as acid sensitive.Calcareous stones are readily dissolved in acid, therefore acidic products should not be used on limestones and marbles. It is usually deposited from solids in groundwater. Travertine:A calcium carbonate, usually light in color, travertine can be extremely porous or cellular.
Generally without cleavage, and extremely uniform in composition and texture, oolitic limestone adjusts to temperature changes. Oolitic limestone: Oolitic limestone is a calcite cemented calcareous stone composed of shell fragments, practically non- crystalline in character.Microcrystalline limestone: This is a limestone structure of crystals too small to be seen without magnification.Dolomite: Dolomite is a sedimentary carbonate rock composed of calcium and magnesium carbonate.Also called "magnesium limestone", it contains from 5 to 40% magnesium carbonate.It is generally very coarse and porous, frequently consisting of oyster and sea shells and fragments. Coquina:Coquina consists of raw, unaltered shell fragments, often quite large, loosely cemented by calcite.Oolite limestone is a sub-category of calcarenite. Some calcarenites contain oolites and if the oolites are present in sufficient quantity, the stone is called oolite limestone. Calcarenite: Calcarenite is composed of sand-sized grains of calcite, usually in the form of tiny fossils, shell fragments and fossil debris.The following definitions are from the American Society for Testing and Materials (ASTM) document, "Standard Definition of Terms Relating to Natural Building Stones."
In an effort to improve accuracy in identifying the general categories of limestones at a 'macro' level, the following section contains descriptions of the most common types of limestone, however this information is no substitute for training and experience to correctly identify and catalog stone types. Failure to accurately identify a material to be treated can result in the failure to consider important technical details which subsequently results in irreversible damage to the resource(s). While this is understandable, it does not lessen or eliminate the need to accurately identify the materials which must be treated and maintained. The subtleties which sometimes differentiate between grades and types of stones are frequently beyond the concern and expertise of maintenance workers, building managers and historical architects with responsibility for maintenance of the resources. The actual classification of limestones and marbles can be very confusing to the non-geologists.The same stone can be marketed one time as a limestone and, at another time and place, sold as marble. Oolitic limestone consists of substantial amounts of "oolites" or "ooliths." Oolites are small spherical or sub-spherical grains of concentric calcite.
Limestone deposits can undergo metamorphism during major geological events resulting in a recrystallizing as marble. Limestones may vary greatly in texture and porosity from coquina, which is a matrix of whole or pieces of sea shells loosely cemented by calcite, to oolitic limestones and microcrystalline limestones whose structures are so fine that they can be seen only under magnification. It will effervesce readily in any common acid. It is a soft rock and is easily scratched. Limestone is usually gray, but it may also be white, yellow or brown. Some varieties of limestone have an extremely fine grain. These fossils are frequently visible to the unaided eye on close examination of the stone surface, however this is not always the case. It is commonly composed of tiny fossils, shell fragments and other fossilized debris. Limestone is a sedimentary rock composed principally of calcium carbonate (calcite) or the double carbonate of calcium and magnesium (dolomite).
See also 04400-01-S for guidance on inspecting stone masonry failures. This procedure includes general information on the characteristics and common uses of limestone and identifies typical problems associated with the material.
#OOLITE SEDIMENTARY ROCK MANUAL#
Limestone: Characteristics, Uses And Problem Procedure code: 446001G Source: Outdoor Sculpture Manual - Center For Public Buildings Division: Masonry Section: Limestone Last Modified:
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