Antique Costume Jewelry: Identifying Signed vs. Unsigned Pieces

Authentic antique costume jewelry is primarily identified by examining construction quality, weight, and findings (clasps and hinges). While signed pieces bear specific maker’s marks like “Trifari” or “Coro,” unsigned pieces require attribution through distinct design traits, such as prong-set stones rather than glue, heavy rhodium plating, and specific soldering techniques used by manufacturers like DeLizza & Elster.

Imagine you are at a crowded estate sale in rural Ohio. You are digging through a tangled box of tarnished chains and plastic beads when your fingers brush against something cold and heavy.

You pull out a sparkling brooch. The rhinestones are brilliant, the metal feels substantial, but when you flip it over, there is no name. Is it a $5 piece of junk, or a $300 unsigned “Juliana” treasure?

As an antique dealer for over two decades, I see this scenario constantly. Learning to look past the signature is the difference between a novice and a pro.

How can I tell if unsigned jewelry is valuable?

The biggest myth in the collector market is that a piece must be signed to be valuable. Many top-tier manufacturers, including Schreiner and DeLizza & Elster (Juliana), produced thousands of paper-tagged items that are now unsigned because the tags were discarded.

To determine quality without a signature, look at the setting. In high-quality vintage pieces, stones are almost always prong-set. This means tiny metal claws hold the stone in place.

If the stones are glued in and look cloudy or dead, it is likely lower-quality mass production.

Check the weight. Older base metals (pot metal or sterling silver) are heavier than modern alloys. A piece that feels “light as a feather” usually indicates a lack of quality materials or a modern reproduction.

Where should I look for maker’s marks on vintage pieces?

If a piece is signed, the mark can be incredibly small or hidden in obscure places. You need a loupe to catch them.

Common locations for marks include:

• The back of the pin mechanism itself.

• The flat metal underside of the centerpiece.

• The jump ring near the clasp on necklaces.

• The inside curve of a bracelet clasp.

Identifying these marks manually can take hours. Using the Antique Identifier app, you can simply take a photo and get an instant result.

What are the “Red Flags” that indicate a modern reproduction?

Forgery detection is a critical skill. The market is flooded with “vintage style” pieces that were made last year.

The most obvious giveaway is the clasp. A Lobster Claw clasp was not widely used in costume jewelry until the 1970s. If you see a lobster claw on a piece claiming to be 1920s Art Deco, it is either a fake or has a replaced chain.

Look for “chopped” stones. In genuine antique jewelry, the stones are cut precisely to fit the setting. In cheap reproductions, the stones are often uniform sizes jammed into settings that don’t quite fit, leaving gaps or requiring excess glue.

This era-dating technique is similar to what we cover in our guide on Is It Victorian or Edwardian? Key Differences for Quick Identification.

How does “Attribution” work for unsigned high-end jewelry?

Attribution is the process of confirming the maker based on construction rather than a signature.

For example, DeLizza & Elster (Juliana) pieces are famously unsigned. However, we identify them by their specific “pudding” solder (puddles of solder on the back), open-backed stones, and 5-link band construction on bracelets.

Schreiner pieces are another example. They often used “hook and eye” construction where the settings are hooked together rather than soldered flat. They also famously mounted rhinestones upside down (point up) for extra sparkle.

Recognizing these traits allows you to provide a more accurate condition report and auction estimate for items others might discard.

What determines the fair market value of costume jewelry?

Fair market value is driven by three factors: Maker, Material, and Condition.

Condition is paramount. “Verdigris” (a green waxy corrosion on the metal) is a major de-valuer. It is difficult to stop and eats away at the plating.

Missing stones also hurt value significantly unless they are rare colors that can be sourced from a “donor” piece.

Restoration versus conservation is a tricky balance. Generally, do not clean vintage rhinestones with water, as it damages the foil backing. A gentle wipe with a dry cloth is best to preserve the provenance and finish.

Finally, the replacement value for insurance purposes is usually higher than what you might get at an estate sale, so be realistic when buying to resell.

Related Antique Identification Guides

Expand your expertise with these related guides: Carnival Glass Identification: How the Iridescence Reveals the Age, How Much is a 1920s Vanity Worth? Valuation Factors Revealed, Is It Victorian or Edwardian? Key Differences for Quick Identification

Conclusion

Whether you are sorting through a grandmother’s jewelry box or browsing a thrift store, keep your eyes on the details. The weight of the metal and the setting of the stones tell a story that a signature sometimes forgets. Happy hunting.