First of all, the crystal cup is also a kind of glass. The most important component is silica, but only lead, antimony, zinc, titanium and other substances are introduced. Because this glass has a high transparency and refractive index, its appearance is smooth and crystal clear, so it is called crystal glass. If lead is introduced, it is lead crystal. Lead-free crystals are introduced when substances such as antimony, zinc and titanium are introduced. How to distinguish between the two? A sense of touch. Because the thermal conductivity of the crystal is stronger than that of the glass, it should be cooler than the touch glass when touching the crystal by hand. Second, look at the hardness. The natural crystal has a hardness of 7 and the glass has a hardness of 5, so the crystal can be scribed with glass. Third, look at the refractive power. Lift a crystal cup and rotate it against the light. You will find it is like a beautiful craft, white and clear, reflecting the fascinating multicolored light, because the crystal can absorb the luster, even the ultraviolet light, and the ordinary glassware No gloss, no refraction. Four listen to the sound. Gently tapping or tapping the finger with a finger, the crystal glassware can make a light and crisp metal sound, and sway the beautiful reverberation in the air, while the ordinary glassware only has a boring "squeaky, squeaky" sound.