Milk glass, widely produced in the United States and England from 1835 through the 1980s, was an inexpensive substitute for the luxurious tableware many could not afford. Milk glass, as you would expect, is the color of milk: a rich, glistening white. Because milk glass has been in constant production since the 1860s, there are many pieces to choose from, including lamps, butter dishes, cold-cream jars, and goblets.

For the potential collector, distinguishing between the valuable and the commonplace can be a challenge. For example, an old, rare piece of milk glass can fetch several thousand dollars, while a charming hobnailed butter dish can be bought for $10. And since few American manufacturers marked their glass, it can be difficult to tell when, where, or by whom a piece was made.

Some older milk glass contains quantities of lead and will ring like a bell when tapped. They will also sometimes display brilliant colors around their edges when held up to the light. But newer milk glass also has its selling points: It's plentiful, undervalued, and so sturdy that you can put it in the dishwasher.