Marble is formed of recrystallized metamorphic rock consisting of calcite and dolomite with uniform crystals. Some may also classify crystallized carbonate rock as marble. Calcite usually forms the dominant material and imparts many of its properties to marble, including the most common white to transparent colors. Other colors and translucence are often seen, too. Mineral composition and local geological events during the life of the rock determine the multitude of other features visible, including additional colors from deposits and exposure to other elements, such as volcanic heat. Untreated marble is highly reactive to acids (including wine) and can dissolve in acidic environments and acidic rain. Marble is sensitive to temperature, and thermal expansion (hysteresis) must be taken into account, especially when using thin sheets where the effect will be more prominent.