To determine if it’s real marble, closely examine the surface for a unique, irregular veining pattern formed by mineral deposits. Fake marble may have a repetitive, artificial pattern. Perform an acid test by placing vinegar or lemon juice on a small area; if it fizzes or bubbles, it’s likely real marble. Real marble is heavy and dense, while fake marble made from synthetic materials is lighter. When in doubt, consult a professional to ensure authenticity.