These two terms “mercury glass” and “silvered” are commonly used to describe glass Christmas ornaments. Do they mean the same thing?
The answer, suprisingly, is No! They are not the same thing.
Mercury glass is the common term for silvered glass, which describes glass that was blown double walled, then silvered between the layers with a liquid silvering solution, and sealed.
Silvered Glass is a layer of glass which is coated with a special compound of silver nitrate and sugar water. This is commonly done on the inside of blown glass ornaments to make them shiny. Decorative paint is then also applied to the outside of the glass. This process was invented in Lausha, Germany and copied widely.
By far, the most comm0nly found glass ornaments are silvered glass and not double walled mercury glass.