Is it Marble or Limestone?

By Frederick M. Hueston, StoneForensics.com

 I am often asked by stone restoration contractors how to tell the difference between marble and limestone. It can be tricky and many times the stone sold as marble are really limestone. The following will help you tell the difference between the two.

You can tell the difference between limestone and marble by looking at them, but that may not always be the case. Limestone’s natural colors include gray, tan, and brown, and it often contains fossil impressions. Many organic-rich varieties appear nearly black, while those with even minute amounts of iron or manganese turn the water an off-white to yellow or even red.

When marble is formed with few impurities, it is typically a pale color. It could be blue, gray, pink, yellow, or black depending on the presence of clay minerals, iron oxides, or bituminous material. For instance, the marble from Thassos is the whitest and most pure in the world, and the marble from Bahai is an unusual and expensive variety. White, pink, brown, and even black are just some of the many colors found in marble’s extensive palette.

Marble vs. Limestone: Breaking Down the Differences

‍Marble and limestone are two popular and timeless construction materials, both of which have been used for centuries in a variety of applications. While they may appear similar at first glance, there are a number of key differences between these natural stones that you should be aware of . Marble is a metamorphic rock, while limestone is a sedimentary rock, and this distinction has a significant impact on their properties and there restoration and care. Lets explore the differences between marble and limestone in more detail.

Chemical and Physical Differences Between Marble and Limestone

 Although marble and limestone are both formed from calcium carbonate (CaCO3), the chemical composition of these two materials varies in several ways. Marble is significantly denser than limestone due to its higher levels of magnesium and silicon. Marble is also harder than limestone, which makes it better suited for applications requiring a high level of abrasion resistance. Marble contains a higher percentage of impurities than limestone, which makes it less durable. The differences in the chemical and physical make-up of marble and limestone impact their porosity and durability. Limestone is a highly porous material with a low level of resistance to water and chemicals, while marble is less porous with higher resistance to water and chemicals. The different porosity levels of marble and limestone result in significant differences in durability. Marble is more durable than limestone and is suitable for a wider variety of applications. Of course, there are exceptions. Certain limestone are harder and more abrasive resistant than some marbles.

Color and Texture Differences

 Marble and limestone are available in a wide range of colors and textures, and some of these options are very similar. Limestone is available in blue, green, red, tan and yellow varieties, while white and black marble varieties are commonly mistaken for limestone. These stones are also available in a number of different textures, including polished, honed, and tumbled finishes. Limestone is more commonly available in a white or tan color, while marble is available in a much wider range of colors. The color of both stones can vary widely from one slab/tile to another.

Maintenance and Refinishing Differences

 The level of maintenance and refinishing required by marble and limestone can vary significantly. Limestone naturally resists water and is less susceptible to staining than marble, which makes it easier to care for. Limestone can be cleaned using a wide variety of methods, including the use of a mild neutral cleaner. Limestone is not impervious to staining and discoloration, and the porous nature of this stone can allow particles such as soil and dust to become trapped within the stone. Limestone can also be susceptible to efflorescence, a white crusty buildup caused by excess salts in the stone. Marble is more difficult to clean than limestone due to its higher level of porosity. Marble can be cleaned with a neutral cleaner and water, but it is important to avoid the use of acidic cleaners. Marble is more susceptible to staining than limestone and requires consistent maintenance to prevent stains from setting in. Marble is also susceptible to efflorescence.

Marble and limestone can be honed with diamond abrasives. Limestone can be abrasive to diamonds causing them to wear quicker than on marble.  Certain limestone may require polishing powders that contain less acid. Its always best to test to be sure.

Marble and limestone are two durable construction materials that have been used for centuries. These two stones are formed from calcium carbonate, but the chemical composition of these stones varies in several ways, impacting their care and restoration. Marble is generally denser and harder than limestone, while also containing a higher percentage of impurities. These differences in chemical composition impact the color, texture, porosity, and durability of marble and limestone. Marble and limestone are frequently used as flooring due to their durability and strength, but they require different levels of maintenance and care. The cost of marble and limestone varies based on the type of stone, color, and size.