Lustro Italiano > Stone Reference > Marble

Natural Marble


Summary

Description:Natural marble is a rock that forms through a natural process. Here is some information regarding natural marble.

Formation Process: Natural marble is a metamorphic rock which forms when sedimentary limestone is heated and squeezed by natural rock-forming processes so that the grains recrystallize.

Appearance: Marble forms in various colors but is usually light colored and can contain streaks of color formed by non-calcite minerals in the rock.

Composition: Natural marble is made up of mainly of calcite and can also contain a significant amount of magnesium carbonate as well as other substances.


Composition of Natural Marble

marble is a calcareous natural stone that is composed mainly of calcium carbonate in the form of calcite. It can contain other minerals (such as magnesium carbonate and other carbonates) as well but it is made up of mostly calcite. Here are some of the components than can be in marble:

  • CaCO3 (Calcium Carbonate)
  • MgCO3 (Magnesium Carbonate)
  • SiCO2 (Silica)
  • Al2O3 (Alumina)
  • Fe2O3 (Iron Oxide)
  • SO3 (Sulphate)
  • P2O5 (Phosphorus)
  • K2O (Potash)
  • Na2O (Soda)

Natural Marble Characteristics

Depending on the amount of and type of impurities in a given marble slab, it can range from white to various shades of grey or tan in most cases. However, marble can occur in various colors. The porosity of a particular stone can vary depending on the composition. Additionally, marble normally has a hardness ranging from 2 to 4 on the Mohs scale of mineral hardness.

Applications and Uses

Marble has been used for many years in a number of ways. For example, marble is the material that many statues are made of and even large state and government buildings are made of marble.

Advantages of Natural Marble

One advantage to marble is that it has a unique, elegant look and adds value to a structure in which it is used. It has "carved" out a place in history as a fundamental material for many of the historical buildings.

Since it is a natural material, marble is compatible with a number of other materials. The colors of marble also make it complimentary to many other materials. Marbles are available in white, tans, greys, and many other neutral colors. Yet, there are non-neutral marble colors as well.

Marble's Disadvantages

One drawback to using marble is that it is a calcareous stone. Calcareous stone is stone that contains calcite. Calcite (a form of calcium carbonate, or CaCO 3) is susceptible to acids. In addition to acid susceptibility, marble is also relatively "soft" as far as stone goes. Additionally, marble is porous, which means it can be susceptible to staining via liquid substances. Yet, there are ways to care for and maintain marble.

Care and Maintenance

Caring for natural marble is simple. However, simple does not necessarily mean it is easy. Since marble is calcareous (composed of calcite), it requires immediate clean up of acidic liquids that could mar the appearance if not removed right when the spill happens. Additionally, regularly sealing marble can help protect it from staining that could occur from colored liquid that could get into the pores of the stone and discolor it. Here are some practical steps that can be taken to care for and maintain natural marble.

  1. Make sure to initially seal marble countertop surfaces to help them resist oil and water based stains.
  2. Use a pH neutral cleaner on your marble surfaces. Acidic cleaners breakdown the sealer and allow stain causing liquids to penetrate the pores of the stone.
  3. Periodically use an impregnating sealer to renew the seal that was added right after installation.

In addition to the care tips above, you can use a fortified natural stone polish on the surface of natural marble countertops (not flooring) to build up the seal a little at a time. By using the pH neutral stone cleaner and natural stone polish, you can consistently maintain the appearance of your marble surfaces.

With marble there is also a need to have an effective etch remover on hand to care for etching that can occur on marble surfaces. Etching occurs when acid dissolves the calcite in the marble, leaving a dull spot.

As we have seen, marble is a very practical natural stone that can be used for a number of applications. It offers advantages as well as some drawbacks. The beauty and cost effectiveness of marble though, may make it a good choice for some of your projects.