Crystal Clear

Over all the years that I've been collecting (and re-selling) vintage and antiques, I continue to be amazed at how much glass and crystal there is on the market. Most vintage glass and a good amount of crystal sell for pennies on the dollar. With crystal, in particular, low prices have confounded me. In my mind, crystal in its natural form isn't simply found everywhere. I decided I needed to educate myself about glass making a bit more and the perfect source was Corning (www.corning.com.) Right off the bat, I learned that the makers of crystal glassware aren't smashing and grinding those beautiful crystals you see at the Gilsum Rock Swap to make their wares. They use sand — specifically silica sand —the same main ingredient used to make regular glass. All glass is basically just sand heated to an incredibly high temperature (1700 degrees Celsius or 3090 degrees Fahrenheit) until it melts, then cools until it changes to what's called an amorphous solid — or, a molten blob that is then manufactured in various ways to create the millions of glass products with which we're familiar. The difference between glass and crystal is that crystal has been enhanced with metal additives to make it stronger or "harder" than glass and to have a greater shine or luster. As you may know, crystal also creates a musical, long lasting "ring" when tapped. The type of glass commonly used in most manufacturing applications (that is, the glass we're all most familiar with), is called soda-lime glass. It's made of sodium carbonate (soda), limestone and silica sand. While glass can be made by simply melting sand and then rapidly cooling it, the addition of sodium carbonate allows it to melt at a much lower temperature; thus, it reduces the amount of energy consumed in its production. Adding that soda, though, reduces its chemical durability and is prone to dissolve when it meets liquids. Obviously, that's no good, so limestone is added, stabilizing it so it can then be cooled and molded. Glass making gets even more complex when a certain color is desired. Different metal oxides and elements added to molten glass create different colors. Some of the more common ones are cobalt for deep violet blue; iron for green or yellow/brown (often used for wine bottles); copper for turquoise (blue-green or deep red, depending on the oxidation level); gold is used to make ruby or cranberry glass; manganese for purple, amethyst or black; nickel for violet, brown or blue (frequently used for stained glass); and the list goes on. You know what creates that fluorescent yellow or green we know as Vaseline glass? Uranium! I was still left wondering what made crystal the more elevated type of glass; glass that actually is expensive in the collecting world are names like Waterford, Lalique and Baccarat. But just adding the word crystal to your set of wine glasses tagged for sale does up the value regardless of manufacturer name. There are actually a few reasons why this is the case. I found a nice, simple explanation at www.friendsofglass.com. As I'd learned from my initial research, crystal does not contain a crystalline structure. The name comes from the Italian word Cristallo, which was used for high-end, hand-blown glass produced in Murano, Italy. Crystal is a subcategory of glass. In other words, all crystal is glass, but not all glass is crystal. What makes the difference is, again, those added elements. Crystal contains strengthening minerals like lead-oxide, potassium carbonate or barium oxide, all which make the glass stronger and more durable. With this added strength, created crystal can be much thinner as well as molded or blown into elaborate or delicate shapes, which we associate with more sophisticated and practiced craftsmanship. So, there you have it. A simplified understanding of how glass and crystal glass are made. It still boggles my mind at how some truly gorgeous antique glassware just sits unloved at flea markets and antique shops. A final interesting note about crystal: Unlike glass, which is endlessly recyclable, crystal is not. Because of those metal elements added, crystal can't be mixed in the general recycling stream.