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 What is the difference between glass and crystal?

Objects made of glass and crystal are both fragile and translucent. However, crystalware is prized for its fineness and delicate beauty. The crucial ingredient that sets ordinary sturdy glass apart from luxurious crystal is lead. Most common glass items like window panes and drinking glasses are made of soda-lime glass, which is composed of lime, soda, and silica (sand), but no lead. Soda-lime glass was known to man since ancient times. Another variety is heat-resistant glass (the kind used for laboratory equipment)—it is made of silica and boron trioxide. On the other hand, crystal is a type of glass, which contains at least 24 per cent lead oxide. The technique of producing crystal was originally discovered by Englishman George Ravenscroft in 1674. Addition of lead oxide allows crystal to have a higher index of refraction than normal glass, making it sparkle. More the lead, greater is the sparkle. Lead also makes the glass softer and easier to etch to create artistic pieces. Despite its name, crystal glass does not have a crystalline structure.