If you take a look at your natural stone surfaces and notice a mark that should not be there, your first thought might be that the area is stained. Not all marks, however, are stains. There could be a number of other reasons behind the difference in colour. Here are some common causes. Etching If your polished marble surface comes into contact with acidic substances, etching can easily occur. Examples of acidic substances include lemons, orange juice, wine, vinegar and several foods such as tomatoes. The acid from the food or beverage will come in contact with the calcium in the stone and cause the unsightly etched appearance. In order to remove the etching, you will need to re-polish the surface. Moisture marks If your stone surface is porous and you spill water, it can easily be mistaken for a stain. The best thing to do is to allow the