Depression and Mercury Glass
I'm very interested in collecting Depression glass. What do I look for to know if I'm getting the real thing? Should I look for any kind of markings or numbers?
-- Mary Margaret Zavalydriga, Horn Lake, Mississippi
Depression glass is the term for the colored or transparent glassware that was mass-produced in the United States during the 1920s and 1930s. This colorful glassware, an inexpensive and cheerful antidote to the dark days of the Great Depression, was not actually known by its current name until the 1970s, when collectors named it. Pink is the most commonly found color of Depression glass available today, followed by green. You can also find it in red, amber, yellow, blue, white, and clear.
The value of Depression glass has been rising steadily in recent years. A 10.5-inch dinner plate, for instance, was valued at $16 in 1983 but sells for $35 today. Yet the cost of most Depression glass is still quite reasonable. A cake plate could sell for as little as $13, a sugar bowl for $7, and an attractive footed tumbler for $25.
Many pieces were never marked, so the lack of identification doesn't necessarily have a bearing on the value or authenticity of the piece. Among the companies that did mark their glass was Heisey, whose brand was an "H" inside a diamond shape. The symbol on Federal's glass was an "F" inside a shield. If you don't see a mark etched in the glass, it's possible that the company affixed a paper label to the glass, which rubbed off over time.
Because you can't rely on identifying marks, the best way to learn to spot Depression glass is to research the subject and talk to other collectors. "The Daze," a newspaper devoted to Depression glass, and books like "The Collector's Encyclopedia of Depression Glass" by Gene Florence will help get you started. Signs that a piece might be a reproduction include a somewhat crude pattern and an inconsistent, muddy color.
Q: I purchased a set of mercury-glass salt and pepper shakers at a thrift shop. They have a small amount of old salt encrusted on the top of the shaker, and I would like to know how to clean it without harming the finish.
-- Jacqueline Stallone, Ocala, Florida
Mercury glass, which is often called silvered glass, has neither mercury nor silver in it. It is, in fact, clear glass that has been mold-blown into double-walled shapes and coated on the inside by means of a silvering formula inserted through a hole in the bottom. The hole is then sealed or plugged. Some silvering formulas are composed of silver nitrate, others from alcohol or ammonia, and others from oil of cassia or tartaric acid.
To remove the encrusted salt from mercury glass, a warm, damp rag should be sufficient. You can use ammonia since you don't have to worry about harming the finish (it's the glass you're cleaning, not the finish within it), but don't use a scouring pad or the glass could be scratched. Don't put mercury glass in the dishwasher or submerge it in water; if water gets between the layers of glass, it will harm the silvered finish. Exposure to air and humidity can destroy the silvering through oxidation, so if your mercury glass has lost its seal in the bottom, plug the hole with a small piece of cork or wax.