Some may have been gifts, others have long forgotten impulse purchases.
Either way, if you have old or broken jewelry that's piling up in a drawer or a box in your home, Blue Leaf Estate Auction 's Rowlan Hill has some advice on how to determine if it's trash or treasure.
First, take it all out and sort it; gold in one pile, silver in another. Set aside the obvious costume jewelry. It can also be valuable, but try not to mix it in with the real metals and gems.
Next, run a kitchen magnet over the metals. Hill says real gold and silver won't attract to the magnet. If the item is too heavy or has a lot of plastic on it, this may not work, but it's a good first step, according to Hill.
Another good tactic? Check the feel. Real jade will be cool to the touch, even if you press it against your face for a few moments. A real pearl will feel rough against your teeth if you gently rub it against them.
What about for potentially high-end watches and gemstones? Best to leave those to the experts to determine what's authentic, Hill says.
Glendale Pawn & Jewelry's Stan Grossman said it's amazing how many people really don't know much about the jewelry they own.
Costume jewelry serves as a good example -- it may still have big value. Grossman has sophisticated testing methods that can determine whether something is real or just a really good fake.
"There's a relatively large market for costume jewelry. Just because you say it's costume, doesn't mean it's worth nothing. Some costume jewelry is very valuable," Grossman said.