Crystal is generally heavier than glass. This is due to the composition and manufacturing process of both materials. Crystal is typically made from high-quality glass that contains lead oxide, which increases its density and weight. For instance, lead crystal, a common type of crystal, can be up to 30% heavier than regular glass. The lead oxide content in crystal makes it more dense and, consequently, heavier. In contrast, glass is usually made from a mixture of sand, soda ash, and limestone, which are less dense and lighter. According to the U.S. Geological Survey, the density of typical glass ranges from 2.2 to 2.6 grams per cubic centimeter, while lead crystal can have a density as high as 4.0 grams per cubic centimeter. This significant difference in density directly translates to a difference in weight.