Glass disease, also known as devitrification, is a condition that occurs when the surface of glass becomes cloudy or discolored due to the presence of impurities or defects. It is often caused by exposure to extreme temperatures or humidity, or by the presence of certain chemical contaminants.

Glass disease can affect all types of glass, including windows, mirrors, and decorative objects. It can be caused by a variety of factors, including poor manufacturing practices, improper handling or storage, or exposure to harsh environmental conditions.

There are several different types of glass disease, including crystallization, which is caused by the formation of small crystals on the surface of the glass; iridization, which is caused by the formation of a metallic or rainbow-colored film on the surface of the glass; and blistering, which is caused by the formation of small, raised areas on the surface of the glass.

Glass disease can be difficult to treat, and in many cases, the only option is to replace the affected glass. In order to prevent glass disease, it is important to handle and store glass carefully and to protect it from extreme temperatures and humidity.