Marble is defined as any limestone that will take a polish. Limestones and therefore marbles are composed of minerals of calcite or dolomite. Colored marbles are the result of other minerals mixed with calcite or dolomite.Marble has many common characteristics. No matter what color, marble will usually have some type of veining running through it. The veins are usually different in color than the main color of the stone. There are, however, exceptions to the rule. Some marbles such as Thassos will have little or no veining. Marble is relatively soft when compared to other stones such as granite. It will scratch very easily. Marble is also very sensitive to acidic chemicals. Vinegar is acidic and will leave a dull spot on marble. Avoid the following acidic materials from coming in contact with your marble: Vinegar, lemon, tomato and tomato sauce, bleach, coffee, urine, vomit, tile cleaners, X-14, toilet bowl cleaners, and cleaners with lemon.