As Valentine's Day draws closer, I feel a little nostalgic for vintage jewelry. Opening up my jewelry boxes and uncovering lockets of love, it's like looking back on memories stored away in these silk-lined boxes.

In the 16th century, lockets held secrets of romance, perfume or even poison. In the 1900s, lockets were being mass-produced so that most folks could afford to purchase them, and they were being worn not just as a heart on a chain, but also on pins and as a charm on a bracelet.

By the mid 1940s, they were considered costume jewelry and were all the rage by young love and also known as the "sweetheart" jewelry. During World War II, lockets were even being sold at the post offices for soldiers to send to their girlfriends, fiancees and wives.

What to look for

The antique lockets collectors pay big dollars for are those made of 18- to 24-karat gold and often have diamonds or other gemstones, engraved with ornate decorations and monograms and have protective glass inside. Looking online for antique or vintage can be fun, but before you drop $100 or more, it is better to be able to look over your piece in hand. Check the condition of the piece, such as the interior of the locket, the finish and the hinges. Stones and gems should be clear, not cloudy. Know the terminology: "Antique" means that a piece is 100 years old or more; "vintage" is under 100 years old.

Newsletter signup for email alerts

Pamela Wiggins, my resource for this column, is also the author of "Warman's Costume Jewelry Identification and Price Guide."

"Antique lockets in oval and round shapes are pretty common," Wiggins said, "but hearts and book form that looks like a book or a scroll are rarer and are more collectible, along with a hand-carved bone locket. As a collector, check the back of a piece for repairs and alterations, which reduces value. Watch out for improvements such as replacement modern stones, which can look out of place in an older setting. Ask a specialist to test gold content. Look for maker's mark on clasps or on pin backs.

"Avoid altered or damaged pieces unless you are into the jewelry repair to resell. If you are not into repairing, find a specialized restorer to test loose stones. When buying antique and vintage pieces, do expect a bit of wear and tear on enamel, but avoid pieces with significant chipping or touch-ups."

To clean and care for antique and vintage jewelry, Wiggins said, "do not soak jewelry in liquids, which can loosen crystals from their settings or even discolor the stone or the finish, but you can clean with a lightly dampened cloth or a cotton swab. Remove tarnish from silver-gilt pieces with a jeweler's polishing cloth, but don't buff very hard, as gold plating can rub off. And finally, store in a nice padded box or a velvet bag to avoid damage."

Where to find

Today vintage lockets can be found almost anywhere online, at antique shops, at flea-markets, and in secondhand thrift stores. You may even find them at auctions, or in your mother's, your grandmother's or even your own jewelry boxes.

Kristen Dickenson, Max Boutique at Treasures Under Sugar Loaf, Winona: "I have about 40-80 heart necklaces and various other Valentine's Day jewelry. They range in price from $1 to $22, depending on design. I seem to have quite a few college-age girls and career women that are purchasing Jewelry."

Kristen does have a few marked pieces, for example the Avon 1980 caged pearl heart pendant and the 1970 Avon large black oval faux locket with a pink rose with a back mirror. Also a 1980 dual heart locket stamped from Korea and an Amethyst heart pendant that has a DM (Danbury Mint) stamp on the pendant only. Kristen's prices are right within the current market value.

Sarah Kieffer, Sarah's Uniques and Jim's 'Man'tiques, St. Charles: "Some of them are marked with the maker's mark, some have the date, and some say where they are made. As you know, I love to display my valentine jewelry this time of year! I do have several heart lockets."

Did you know Valentine's Day is the second-largest holiday for giving jewelry as a gift? Chris Rand Kujath, Old River Valley Antique Mall, Stewartville, knows. "We did sell a lot of heart lockets and necklaces at Christmas, the number-one time of the year, followed by Valentine's Day, then Mother's Day. Most of our lockets are costume jewelry that are not marked, ranging from $2.95 to $50."