Lead crystal symbolises the beauty and purity of glass, and there is a certain elegance to serving drinks in a crystal glass. Although all crystal is glass, not all glass is crystal. The British standard for determining lead crystal is that the glass must contain at least 24 per cent lead oxide. There are certain things you can do to tell if your glass vases and stemware are lead crystal or regular glass.
Hold the crystal glass in one hand. Flick the fingertips of your other hand gently against the crystal. Listen for the clear ringing tone and watch for the subtle vibration from the crystal glass. Do the same thing with the regular glass. Listen for the tone from the glass and you should hear a "ping" or muted sound. The sound is completely different from the crystal glass. Observe the glass and there will be no vibration.
Hold a crystal and a regular glass up to the sunlight or a bright light. Notice that the light passing through regular glass does not have the refractive effect as the crystal glass. Note also how the crystal glass produces a rainbow effect because of the embedded lead oxide particles. Light passing through regular glass does not produce this sparkle.
Compare the glasses by weight. Lift a crystal glass and a regular glass and rest each glass in the palm of each hand. By paying attention to the weight you can tell which glass is heavier. Adding lead oxide to a glass increases its weight, so the crystal glass should feel heavier than the regular glass.
Admire the beautiful and intricate patterns etched into your lead crystal glass. Note that the regular glass does not have the patterns and designs. This is because regular glass is harder than the lead crystal glass, making it much more difficult to create designs. Adding lead oxide to lead crystal glasses softens the glass, enabling the manufacturer to be more creative with patterns and designs.