Costume Jewelry vs. Fine Jewelry: How to Tell Them Apart

The difference, in one paragraph

Fine jewelry is made of precious metal (gold, platinum, silver) and set with natural or lab-grown gemstones, and it has a value as material whatever anyone thinks of the design. Costume jewelry is made of base metal (brass, pot metal, steel, or plated versions of those) and set with glass, crystal, plastic or paste, and its value is entirely in the design, the maker and the condition. Neither is automatically worth more than the other. A thin gold chain is fine jewelry worth its weight and little more; a signed brooch from a great mid-century costume house can sell for more than that chain several times over. The sorting job is to tell which is which, and then to price each by its own rules.

Sort with a magnifier, a strong magnet and a kitchen scale, in good light, and put everything with a karat mark or a signature to one side for research before anything is priced. The broader question of how jewelry moves through an estate, and how companies handle it, is covered in selling jewelry from an estate; this guide is about the first sort.

Karat marks and other metal marks

Fine jewelry is almost always marked, in the United States by law once it is described as gold or silver. Look on the inside of a ring band, the clasp or the tag near the clasp on a chain, the back of a pendant or brooch, and the post or back of an earring. Marks are tiny and worn; a jeweler's loupe or a phone camera zoomed in will find them.

A mark is a claim, not proof. Base-metal pieces stamped 14K exist, and so do unmarked antique gold pieces whose marks wore away or were never applied. Treat the mark as the first sort and confirm anything valuable with the tests below or at a jeweler's counter. The guide to telling sterling from plate covers silver marks in more depth, and the same logic applies.

Tests you can do at home

None of these is conclusive alone, and together they sort most of a box correctly.

• The magnet. Gold, silver and platinum are not magnetic. A strong magnet that pulls a piece is telling you it is steel or has a steel core, and it is costume. A magnet that does nothing proves nothing, because brass and pot metal are not magnetic either. Test clasps separately; a gold chain often has a steel spring inside a gold clasp.
• Weight in the hand. Gold is dense. A gold chain feels heavier than it looks; a plated chain of the same size feels light. Platinum is heavier still. A kitchen scale that reads to a tenth of a gram lets you compare a piece with its marked size and with pieces you know.
• Wear points. Plating wears through where a piece rubs: the back of a ring band, the clasp, the points of a chain, the edges of a bangle. Look for a different color showing under the gold, usually copper-pink, brass-yellow or gray. Solid gold wears to more gold. Green or black marks on the skin where a piece was worn point to base metal.
• Color and tarnish. Gold does not tarnish. A "gold" piece that has gone dull, dark or greenish is plated or gold-toned base metal. Sterling tarnishes to gray-black and polishes to white; plated silver often tarnishes with a bluish cast.
• Construction. Fine jewelry usually has stones held in prongs, bezels or channels, with the backs of the stones open so light passes through. Costume usually has stones glued in, often with closed or foil backs, and the metal is cast in one piece with less finishing.

The acid test, a drop of testing acid on a scratch on a touchstone, is what jewelers and gold buyers use to confirm karat, and it is not worth doing at home. Any jeweler will test a piece in a minute, and most will do a handful free if you are considering selling. For a full box, take the pieces that passed the tests above rather than the whole tangle.

How to tell real stones from glass

A stone in a fine setting is usually real or lab-grown; a stone in a base-metal setting is almost always glass or crystal. That rule alone is right most of the time. Beyond it, a loupe and a few habits help:

• Bubbles and swirls. Glass often shows round bubbles or curved swirl lines inside under magnification. Natural stones show angular inclusions, crystals, feathers or needles, or nothing at all.
• Wear on the facets. Glass is soft and its facet edges round off and chip with wear. Diamond, sapphire and ruby keep sharp edges for a lifetime.
• The fog test for diamonds. Breathe on the stone. A diamond clears almost at once; glass and most imitations stay fogged for a second or two. Cubic zirconia also clears quickly, so this test only rules out glass.
• Weight, again. Cubic zirconia is noticeably heavier than a diamond of the same size; if the stone seems too heavy for the setting, it may be one. Only a jeweler's tester or a lab report settles diamond against moissanite against lab-grown.
• Foil backs and closed settings. A stone with a metallic backing to make it sparkle is rhinestone or paste. That is what costume is supposed to have, and it is not a flaw in a costume piece.
• Pearls. Run a pearl gently along the edge of a front tooth. A real pearl, natural or cultured, feels faintly gritty; glass or plastic feels smooth. Real pearls also vary slightly from one to the next and feel cool. A knotted strand with a marked clasp is a good sign; a strand that is perfectly uniform is usually imitation.

A stone that might be real and significant, a large colorless stone in a platinum or gold setting, a strong red, blue or green stone in a fine mount, belongs with a jeweler or a gemologist before the sale, and possibly with a lab report. That is covered in appraisal versus estate sale pricing: an appraisal is worth its fee for a handful of pieces and a waste of money for the rest of the box.

Signed costume jewelry that is worth real money

This is the part of the box families throw away. Costume jewelry from the great twentieth-century makers is collected seriously, and a signed piece in good condition can sell for far more than the family imagines a "fake" could. What makes it valuable is the maker's signature stamped on the back, the design, the era and the condition, in that order.

Names that collectors search for include the mid-century American costume houses (Trifari, Coro and its Corocraft and Vendome lines, Miriam Haskell, Eisenberg, Weiss, Hobe, Boucher, Schreiner, Hattie Carnegie, Kenneth Jay Lane) and the costume lines of the great fashion houses (Chanel, Christian Dior, Schiaparelli, Yves Saint Laurent, and later Givenchy, Lanvin and others). Bakelite, the early plastic, is collected in its own right, especially carved or in bright colors, and is often unsigned.

A few things to know while sorting:

• Turn every piece over. The signature is on the back of a brooch, on a small plaque on a necklace clasp, on the back of an earring clip. It is often tiny.
• Sets are worth more together. A brooch with its matching earrings, or a necklace and bracelet in the same design, is a parure or demi-parure and sells for more than the pieces separately. Keep them together.
• Condition is everything. Missing or replaced stones, worn plating, darkened rhinestones ("dead" stones where the foil has gone), a broken clasp or a missing clip all cut the value sharply, because collectors want original and complete.
• Unsigned is not worthless. Some of the best mid-century pieces were never signed, and a well-made unsigned piece with hand-set stones and a quality clasp still sells to dealers who recognize it.
• Bakelite is tested with heat, not chemicals. Rub the piece hard with a thumb for a few seconds and smell it; Bakelite gives a faint chemical, formaldehyde-like smell. Do not use hot pins or solvent, which damage it. Beware of newer plastic copies, which are common.

The guide to overlooked treasures lists costume jewelry beside the other small things that get bagged for donation and should not be, and fakes and reproductions covers the reproduction signed pieces that now circulate.

What each kind is worth

Fine jewelry has a floor and a ceiling. The floor is the metal: weigh the piece, note the karat, and the day's gold or platinum price gives the value of the metal in it, from which a buyer deducts a margin for refining. Stones add to that only if they are worth resetting, and small diamonds and colored stones in ordinary settings add less than families expect. The ceiling is the piece as an object: a signed piece from a fine jeweler, a period piece (Victorian, Art Nouveau, Art Deco, mid-century) in good condition, a significant stone with a lab report, or a designer name can sell for several times the metal value at auction or through a dealer. Everything between the floor and the ceiling depends on condition, maker and local demand, and the only honest way to find out is to compare recent sold prices for similar pieces, which the guide to finding out if something is valuable explains.

Costume jewelry has no floor. Unsigned, worn or damaged costume sells at estate sales for a dollar or a few dollars a piece, often by the bag, and much of it goes to donation. Signed pieces by collected makers in good condition sell for tens of dollars to, for the rarest designs and the fashion-house pieces, a few hundred or more. Ranges are wide, prices move with fashion, and a piece's value depends on the exact design and its condition as much as on the name. A signed piece with a replaced stone is a different object from the same piece complete.

Two figures families remember are usually the wrong ones: what a piece cost new, and what an old insurance appraisal said. Retail and insurance replacement value are far above what any buyer pays for a used piece, which is the subject of the appraisal guide.

Where each kind sells best

The right route is different for each pile, and using the wrong one costs money in both directions.

1. Significant fine jewelry. A signed piece, a period piece, a large or fine stone. A jewelry auction or an estate jewelry dealer reaches buyers the sale floor never will. Get two opinions before consigning, and ask what the seller's commission and any photography or lab fees will be.
2. Ordinary fine jewelry. Broken chains, single earrings, thin bands, dated pieces nobody will wear again. Worth their metal. Weigh it, check the day's price, and get quotes from a jeweler and a refiner rather than the first walk-in gold buyer you see; the spread between offers is often wide. Pieces that are wearable can also sell well on the sale floor, priced above metal, if the company handles fine jewelry properly.
3. Signed costume. An estate sale is a good place for it, because costume collectors and resellers follow sales and come early. Ask the company to price signed pieces individually, name the makers in the listing and keep them in a case. A large signed collection can also go to a specialist dealer or an online auction lot by lot.
4. Everything else. The sale floor, in trays or bags, priced to go. Resellers buy costume by the lot for parts and repairs.

At the sale itself, jewelry belongs in a locked case or at the cashier's table with one person responsible for it, never spread on a dresser. It is the easiest thing in the house to pocket, and companies that handle it well say so in their contract. The guide to estate sale security covers what to ask. And if the estate is in probate or several relatives have a claim, record what was sold and for how much; rules on estate property vary by state, this is not legal advice, and the attorney handling the estate can say what records are needed.

What to do next

Empty the jewelry box onto a towel in daylight. Pull out everything with a karat or platinum mark, everything with a signature, every strand of pearls with a marked clasp, and anything heavy for its size. Run the magnet over the rest. Photograph the marks and signatures, keep sets together, and put the whole lot somewhere safe until it has been priced.

When you are ready for a professional opinion on the jewelry and the rest of the house, describe the estate once and local estate sale companies will reach out to you, free; ask each how it handles jewelry. The guides to selling jewelry from an estate and vintage clothing, handbags and accessories cover the closet and the dresser where the rest of the small valuables tend to be.

Frequently asked questions