<p>Crystal glass is nowadays the common term for leaded cut hollow glass with a high refractive index. Through histiory the term crystal glass stood for loads of different glass types. In the 15th century crystal clear glass from Venice was termed "cristallo". Later all brilliant and colorless glasses - which could achieve a high refractive index without losing any transparence - were termed crystal glasses. A further form of the crystal glass is the leaded crystal glass. The invention of this glass in the baroque time period has been attributed to the English. Leaded crystal glass is a crystal clear glass which is very suitable as a cut glass. Crystal glass is preferably used for high quality and high value luminaires because of its excellent light refractive properties.</p>