A technique unique to glass, air twist requires very high quality material for success. When sparkling lead crystal became common in 18th-century England, the air twist technique spread rapidly.
A popular term for colorless lead glass, which has a high refractive index and consequently is particularly brilliant. In the United Kingdom, glass described as crystal must contain a defined percentage of lead oxide. Today, the word is often used to describe any fine glass tableware.
A type of decoration in the stems of 18th-century and later drinking glasses, made by twisting a glass rod embedded with threads of white glass, threads of colored glass, columns of air (air twists), or a combination of all three.