When beginning the process of picking a stone for your home or business, it is important to factor in the different characteristics of the natural stones. Some natural stones are softer than others, which makes the stones more susceptible to etch. The process of etching takes place when there is a reaction between an acidic substance and the calcite and dolomite in a natural stone. There tends to be more calcite and dolomite in marble’s and quartzite’s, which makes those stones more susceptible to etching.
The pictures below show the testing we conducted using lemon juice, which is a commonly used acidic substance. The four samples shown here from left to right are Super White marble, White Carrera marble, Burlesque quartzite, and Taj Mahal quartzite. We sealed the left half with Miracle Sealants Company’s 511 Porous Plus sealer, and kept the right half unsealed.
After we sealed the left half of the samples, we placed a few drops of lemon juice on both sides. The following pictures show the results of leaving the lemon juice sit on the stone for 45 minutes. As you can see, there are etch marks on both sides of the samples. This shows that etching can occur even when the stone is sealed.
In the second picture below are the Super White marble and White Carrera marble with the etch marks on both the sealed and unsealed sides. Both of these stones are marble, which tends to be softer than granite's and most quartzite's.
In the third picture below are the Burlesque quartzite and the Taj Mahal quartzite. In the Burlesque, the etch marks can be clearly seen on both the sealed and unsealed sides of the sample. However, the Taj Mahal quartzite that does not have any etch marks. It is likely that the Taj Mahal is made up of different minerals than the Burlesque, which makes the stone harder than the others.