How pure is that gold bracelet? Maybe it isn't even real! Emeralds can often be enhanced by filling them with oil. But over time, the oil can leak out. And a diamond can appear more brilliant through what's called fracture-filling. But that also makes diamonds more likely to shatter, so you have to be careful when they're repaired and cleaned.
You should ask whether a gemstone or a diamond is imitation, treated, or synthetic. And if the jeweler can't or won't tell you, that's your cue to shop somewhere else. Buying gold? Look for a karat mark, which indicates quality, and a manufacturer's trademark, so you know whose work it is.
But Consumer Reports Money Adviser's top tip for protecting yourself is to deal with a reputable company. Members of the American Gem Society must abide by a strict code of ethics. You can go to the AmericanGemSociety.org to find a reputable jeweler in your area, as well as anywhere in the country.
Whatever jewelry you buy, make sure you get the details in writing. Consumer Reports also says to consider an appraisal from a certified jewelry appraiser. And be sure the return policy gives you at least enough time to return something if it isn't what you expected.