Iran Stone

Marble Stone

What is Marble

Marble is an extremely hard, metamorphic stone composed of calcite(CaCO3).  It is formed as a result of the recrystallization of limestone under the intense pressure and heat of geologic processes.  The effect of this process is the creation of a stone with a very tight crystalline structure and small but definite porosity.  Because of its structure, marble can take a very high polish and is a very popular decorative stone for architectural and sculptural uses. It has been a symbol of beauty in the grand buildings built by emperors. Marble is used in both internal and external applications, and is available in several colors and shapes.Impurities present in the limestone during the recrystallization period affect the mineral composition of the marble which is formed. The minerals that result from impurities give marble a wide variety of colors. The color of marble ranges from the brilliant white of calcite to black, including blue-gray, red, yellow and green, depending upon the mineral composition. Marble that has limonite is yellow, and marble with serpentine is green in color. The purest calcite marble is white in color. Marble containing hematite is reddish in color. The restricted marble porosity, mainly when refined, makes it less susceptible to water damage .Marble is readily dissolved by acids, even very dilute acids .calcium carbonate, the main ingredient of marble, is exceedingly susceptible to acidic agents. it rapidly dissolves in some acids however the actual results of acidic exposure will vary with the nature of the acid.  Marble does not split easily into sheets of equal size and must be mined with care. The rock may shatter if explosives are used. Blocks of marble are mined with channeling machines, which cut grooves and holes in the rock. Miners outline a block of marble with rows of grooves and holes. They then drive wedges into the openings and separate the block from the surrounding rock. The blocks are cut with saws to the desired shape and size. These tiles are either polished or honed. Polished tiles provide a stylish appearance, though are extremely slippery when wet. Honed tiles offer more grip and are considered safe.

Uses of Marble

Marble has always been highly valued for its beauty, strength, and resistance to fire and erosion. it is considered the stone for the emperors and gods. Marble has many decorative and structural uses. It is used for outdoor sculpture as well as for sculpture bases; in architecture it is used in exterior walls and veneers, flooring, decorative features, stairways and walkways. The ancient Iranian & Greeks were good user of marble in their buildings and statues. Carrara marbles from the Apuane Alps in Italy were subsequently exploited and today are still the most sought white marbles for statuary work .The Italian artist Michelangelo used marble from Carrara in a number of sculptures. The ancient Greeks are famed for their genius in forming statuary and basreliefs from Parian marble, one of the finest and purest white marbles ever discovered. Marble has decorated the corridors of cathedrals and historical places. Marble tiles cover the floors of the affluent and also beautifies the baths of more moderate homeowners.
Very pure calcite marble is used for most statues. They are translucent. Large blocks of colored marble are used for columns, floors, and other parts of buildings. High-grade marble graces the exteriors of many of the world’s finest buildings and, because of its high resistance to heat, it is being used increasingly in the erection of fireproof buildings, for floors, and for the overlaying of inside walls and ceilings.  Marbles are suitable for internal and external applications. However, due to modern-day environmental pollution, the polish on marble used for external applications may not be durable.
Smaller pieces of marble are crushed or finely ground and used as abrasives in soaps and other such products. Crushed or ground marble is also used in paving roads and in manufacturing roofing materials and soil treatment products. Among the many other uses of this so-called dimension marble, in addition to decorative work and monuments, are tiling, washbasins, interior window sills, vases, chimney pieces, veneer, ashlar, and electric power panels
The way in which the stone is used may be a factor in limiting or controlling the severity of exposure.  The use or function of the marble may also affect the feasibility of applying certain treatments, but type of use is not the primary factor in the major types of deterioration and damage to which marble is susceptible.

Physical Properties of Marble

Physically, these are recrystallized, Hard, Compact, fine to very fine grained metamorphosed rocks capable of taking shining polish.

Chemical Properties of Marble

Chemically, they are crystalline rocks composed predominantly of calcite, dolomite or serpentine minerals. The other minor constituents vary from origin to origin.

Weather Effects On Marble

The forces of nature may produce a decaying effect on the look and structural reliability of marble. These agents include temperature, snow, rain, wind and atmospheric pollutants. Rust can only affect marble if there are some ferrous (iron-based) metals in the marble somewhere.
Chemical weathering is worse for marble because it is composed of calcite, which dissolves very easily in hydrochloric acid. Even a small amount of acid can make the marble weather quickly.Weathering agents normally act in combination with the other agents to increase the deterioration of marble. Rain water, particularly in combination with the atmospheric gases, may cause dissolution of the marble, generating salt movement within the micro-structure. Temperature can intensify the deterioration rate, and the patterns of salt relocation within the stone. High temperatures normally multiply the chemical changes. Sudden changes in temperature can cause stresses due to the differential in expansion. Moisture is considered to be one of the foremost causes of the problems that may happen. However other troubles like erosion due to wind and mutilation may also occur.