Hurricane lamps have a glass bottom that sits on a metal or brass base that holds oil. The lamp's chimney -- a long, clear glass cylinder -- protects the oil-soaked wick from drafts; that's how the lamp got its name. Some hurricane lamps have an additional glass globe around the top of the chimney for decoration. Oil lamps were common before the widespread use of electricity, so they are a common item in antique shops and flea markets. Spotting a hurricane lamp is easy, but you need a closer look to ensure it's a true antique.
Examine the glass. Older lamps are usually made from hand-blown glass, which usually contains imperfections from air bubbles and other small errors that occurred during the glass-blowing process. Replicas usually are made by machine or with a mold, so they usually have no imperfections in the glass.
Compare sizes. For practical reasons, antique hurricane lamps are large enough to enable them to burn for long periods of time before running out of oil. Smaller hurricane lamps usually date from more recent times, when they were decorative rather than a major source of light.
Learn your colors. Hurricane lamps are usually handpainted with a variety of different designs and colors. However, hurricane lamps date back to the 1700s, when there weren't as many colors to choose from as there are today. If you're looking for a specific time period, learning what colors were available in that time frame will help you weed out imposters.
Detect any markings. Look closely for any company stamp or production dates on the metal parts, such as the base or the portion that contains the wick. If you find markings, this can be a clue as to who made the lamp -- and when.
Check out the base. Older lamps have a heavy metal base, but newer versions are not very heavy. Also look at the bottom of the glass base. An original usually has a rigid or jagged edge where the bottom was chipped off to sit in the base properly. A replica usually has a completely smooth edge.
Stick to reputable antiques dealers, especially if you're new to the antiques game. Not everything listed as antique really is. Unscrupulous dealers might try to pass an item off as an antique in order to get a higher price, so buy from dealers you trust.
Ask questions about the lamp. If it's genuine, the seller should have plenty of information to share about the lamp. If you still aren't convinced, ask someone who is knowledgeable on the subject, such as an appraiser, to check out the piece.