ROCK CRYSTAL: natural mineral, grown from Silicium Dioxide. Semi-precious stone, half transparent, partly with the patterns of a unique from. Rock crystal is hard to process because of need of particles selection, so manufacturing process is an art. Rock crystal is used in chandeliers quite rarely because of an unusual look and very high price.
LEAD CRYSTAL: artificial high quality glass which consists of quartz sand, Potassium Carbonate and Lead. The latter adds an extra transparency and capability for splitting the light. Lead crystal is relatively easy to process because of being soft, but it also easily destroyed. In the near past lead crystal was the only option for achieving even facets and sparkles, but nowadays limitations of lead usage in home appliances may push it out of the lighting devices.
OPTIC CRYSTAL: lead-free high quality glass which consists of quartz sand, Calcium Oxide, Potassium Oxide and Silicium Dioxide. It has very good transparency and splits light into color spectrum. That's why it is most commonly used in lenses. Optic Crystal is relatively new material for lighting and it creates effect nearly similar to the one of lead crystal but it is cheaper and safer at the same time.
PLAIN GLASS: - a regular "bottle" glass. Plain glass is used in inexpensive chandeliers but it still can look really nice after highly-skilled hand cutting.
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