Glass and Crystal – What’s the Difference?

Some of the most striking plaques, trophies and other award items are those made of glass or crystal. But what’s the difference between these two materials?

The short answer is that while all crystal is glass, not all glass is crystal. Humans have been making glass out of silica, or silicon dioxide (sand, basically) and other raw materials for well over 4,000 years, and possibly even longer. But it wasn’t until the 17th century that crystal glass, originally called flint glass, was developed.

An English innovation

It was at that time that a glass merchant’s guild in England, the Worshipful Company of Glass Sellers, began to be unhappy with the quality of glass they were getting from suppliers in Venice. They asked a glassmaker named George Ravenscroft to see if he could come up with a better homegrown product.

It turns out that he could. By adding lead oxide, Ravenscroft came up with crystal, a type of glass that was more solid, heavy and durable than regular glass, and also shows more brilliance and clarity. This discovery ushered in a wave of innovative and graceful design in the English glassware industry.

Today crystal glass is made not only with lead oxide, but also with oxides of barium, zinc and potassium. In each case the result is the substantial, sparkling glass material that goes into producing both fine quality drinkware and lustrous award items.

The curious nature of glass

Glass, whether crystal or not, is a pretty intriguing substance. You may have heard the claim that it’s actually a very dense liquid rather than a solid, but this is a misconception. It’s actually what scientists call an amorphous solid – something between a solid and a liquid.
When glass is made, the silica or other raw material is melted, then cooled to a temperature below the transition point at which it becomes a glass. This process is not the same as freezing, so the glass is not really a solid, but its molecules are moving so slowly that it acts like one – holding its shape, for instance.

But you don’t need to know the technical details of how glass and crystal are manufactured to appreciate their lucid clarity and light-scattering effects, or the flowing lines of a piece of hand-blown glass art. Or to know that both types of glass make for elegant, eye-catching plaques, trophies and awards.