Crystal

This is glass of a particular sort. The inclusion of lead oxide in molten glass increases the end product's refractive index and lowers its working temperature - an important discovery given the state of furnace construction of the day. It is probably unsurprising that the addition of lead to glass also increases the weight of the final glass product. Items so produced may have felt more substantial and thus may have been considered more valuable. The crystal chandelier owes its appeal to the lead component. But there are places where, despite the beauty, we do not want to come into contact with lead - in glassware and containers which hold our food and drink. Other oxides have taken the place of lead where this is an issue.