Why are lead crystals more sparkly than glass?
Lead crystal is lead glass that has been hand or machine cut with facets. Lead oxide added to the molten glass gives lead crystal a much higher index of refraction than normal glass, and consequently much greater “sparkle”. Crystal can consist of up to 33% lead, at which point it has the most sparkle. The higher lead content also makes it much more difficult to form crystal during blowing, which is why lead crystal items are more expensive than regular glass.
