Ice

Ice is water frozen into the solid state. Usually ice is the phase known as ice I_h, which is the most abundant of the varying solid phases on the Earth’s surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions. The addition of other materials such as soil may further alter the appearance. The most common phase transition to ice I_h occurs when liquid water is cooled below 0°C (273.15K, 32°F) at standard atmospheric pressure. It can also deposit from vapour with no intervening liquid phase, such as in the formation of frost.