What is the difference between glass and crystal?
The main difference is the lead content. Glass is composed of sodium and potassium. Crystal is also composed of sodium, but in addition, it contains silicone, and has a lead content of 24%. The lead makes the glass heavier and, most importantly, the lead changes the refraction index of the item, which makes it appear brighter and cleaner. Because the refraction index is higher and lead crystal is not as brittle as standard glass, it is possible to make deeper and more complicated cuts in crystal.
Crystal is made by adding lead oxide to glass, which makes crystal heavier than glass. The lead in crystal is what makes it sparkle and reflect colors much more than plain glass. When the lead content is higher – the crystal is a better quality. In Europe, glass must contain at least 4% lead to be called crystal. In the US, glass must have at least 1% lead content to be classified as crystal. In contrast, Swarovski (Swore-off-ski) crystal has at least 30% lead content. Swarovski crystals are regarded as the highest quality machine cut and polished crystal beads in the world. Swarovski crystals are perfectly uniform. This means that the height, width and slope are consistent. Swarovski uses machinery that precisely cuts each crystal. They cut hard materials such as crystal and gems, in a way that they have a hundred identical facets in several directions. This a very complicated task: each direction of the reflected light must first be calculated by computer, simulated in 3D, optimized
The difference is crystal has lead in it! When crystal glass is made, lead in the form of lead oxide, is added to the basic mixture in lieu of the calcium oxide used in making plain glass. The amount of lead used varies between 28% and 32%. It is this lead content that gives crystal its special characteristics of softness and optical The clarity. When light is passed through a crystal the lead causes the rays to refract (bend) causing the myriad of beautiful rainbows inherent with a true crystal. There is no such thing as lead free crystal! Without lead it is just plain glass!
