Iron Oxidation and why some tiles oxidize, and adjacent tiles do not

By Frederick M. Hueston StoneForeniscs.com

Iron oxidation is a common issue that can affect natural stone tiles. When iron within the stone comes into contact with oxygen and water, it can cause the stone to rust and stain. In a recent stone inspection, I came across several tiles that were stained from iron oxidation, which is a common problem in areas with high iron content in the water or soil.

What was strange about this particular case was that only some tiles were stained, while others right next to them were not. This can be confusing and frustrating for homeowners and contractors alike, but there are several reasons why this might occur.

One possible explanation is that the iron content in the stone varies from tile to tile. Some tiles may have a higher concentration of iron than others, making them more susceptible to staining. Additionally, the stone may have been cut from different parts of the quarry, each with its unique mineral composition and iron content.

Another factor that could contribute to this issue is the presence of other minerals in the stone. Some minerals, such as pyrite, can react with oxygen and water to produce sulfuric acid, which can accelerate the process of iron oxidation and staining.

Finally, the staining may be related to the installation of the tiles. If the tiles were installed in a high-moisture area such as a shower or steam room, the increased humidity could exacerbate the problem.

There are several factors that can contribute to the selective staining of natural stone tiles from iron oxidation. It’s important to work with a knowledgeable and experienced consultant who can identify the root cause of the problem and recommend appropriate solutions. With the right approach, it’s possible to prevent and sometimes resolve staining issues and ensure that natural stone surfaces remain beautiful and durable for years to come.