Crystal wine glasses are made from glass that contains lead oxide. Lead oxide is added to the glass to increase the density. When the density is increased, the glass becomes shinier and more reflective. Crystal wine glasses often reflect a brilliant array of color.
Crystal wine glasses are heavier than glass wine glasses since of the lead content. The number of colors that are reflected from the glass really depends on the number of lead that is added to it. The amount of oxide lead added to the piece determines the weight of the crystal.
Hand created crystal wine glasses often have seed bubbles that are visible in the glass. These bubbles are made when tiny pockets or air get trapped inside the glass. That is why, a lot of people wonder why they find imperfections in their crystal pieces. This is because the process of making the glass itself.
The imperfections are often only seen by holding the glass up to a light. They are not a sign that the glass is faulty, but they are more likely a sign that the glass was made by hand. Imperfections are found on even the finest hand crated crystal , and other imperfections include chill marks and slightly cloudy places.