Patti Geolat, chief executive officer of Geolat & Associates, a Dallas-based appraiser of antique jewelry, says a reputable dealer can be your sherpa through the sometimes dizzying world of different styles and periods. “If you’re going to buy it on the street, a tremendous amount of the burden is on you,” she cautions. If you decide you want to skip the middleman and purchase items directly from auctions or private sellers, keep in mind that the process requires a lot of forensic work, says Betteridge. Being a jewelry detective demands the ability to spot details like repairs that were made with cheaper materials or stones that were replaced with newer (possibly less valuable) gems. Your eye will also need to be able to pick up deterioration such as a loose setting that you’ll have to repair before reselling.