A hallmark is a claim about metal, and it is a different article. How to read sterling and gold marks is the lettering: sterling, 925, 14k, a gold-filled fraction, plate. This note is everything that lettering does not settle. A clasp can be newer than the chain. A stone can be glass in a real gold setting. A pearl strand can be coated beads on a clasp that says 14k. A magnet can clear steel and still leave you holding brass. None of that is a price. The karat jewelry guide, the gold-filled guide, the flatware guide, and the costume brooch guide are the objects. This is the check you do with the piece in your hand.
Do not scrape a chain to see the color inside. You will damage it, and a scratch is not a karat. Do not quote a melt number from a comment. Metal prices move, and a buyer’s figure is not a retail price.
Clasps and findings
Findings are the small parts: the clasp, the jump rings, the earring posts, the pin stem, the bail. They are where vintage jewelry gets repaired, and a repair is not a fake. It is a different object from an untouched one, and the listing has to say so.
Look at the clasp before the chain. A lobster claw, a spring ring, a box clasp, and a fold-over are different mechanisms from different habits of making. A bright, unworn lobster on a chain whose links are thin and dark is a replacement until someone shows you otherwise. The solder at the join is the tell. Fresh solder is a different color from the old metal, often a gray or yellow blob that does not match the links next to it. Original solder is still solder. It is just not the only shiny thing on a tired chain.
Read the clasp and the chain as separate metals. A 14k stamp on a clasp does not travel backward along the links. The marks note is how to read the letters. This page is the reason you photograph the clasp and a link, not one crop that flatters the stamp. Earring posts and nuts are the same problem. A gold post with a steel nut is ordinary. A plated post with a gold nut is the disappointment. Test and read each one.
On a brooch, the pin stem has to lock. A C-catch that does not catch is a brooch you cannot wear. Earlier findings, including a simple hook and a safety-pin form, are construction, not a year you invent. The brooch guide is the costume version of this, including pot metal that is bubbling. Fine-jewelry pins fail more quietly: a bent stem, a loose hinge, a missing safety.
Jump rings should be closed. An open ring catches fabric and means the strand or the charm can leave. A dozen cheap open rings on a chain that is otherwise worn are a later assembly. Say the chain was restrung or rebuilt if the findings do not match the wear on the links. A bail that is a different color from the pendant is the same fact. Name it.
Where plating wears through
Plate and gold-filled fail in a place you can point at. The high points go first: the edge of a locket, the corner of a signet, the shoulder of a ring, the outer curve of a bracelet, the back of a band where it rubs a finger. You are looking for a different color. Yellow gold plate over brass goes pale or pink at the corner. Gold over a white base shows gray or silver. Silver plate over copper shows copper. That color at the corner is the layer gone.
Solid karat gold and solid sterling do not do this. They wear thin. A band can go knife-edged. A locket can dent. The color stays the color of the alloy, because there is no skin to breach. If you see a second color only in the scratches and the corners, stop treating the piece as solid. The gold-filled page is the stamp that usually accompanies a thick skin, the fraction and the GF. Plate often says RGP, GP, or nothing. Wear-through is how the nothing gets caught.
Rhodium plating on white gold is a finish and a repair habit. When it wears, white gold can look slightly warmer. That is not brass showing through a costume piece. Do not call it plate unless you can see a base that is not gold. If you cannot tell, say the finish is worn and do not upgrade it.
Enamel, paint, and a gold wash on costume metal fail differently. Paint chips. A wash goes thin and patchy across a surface, not only at one corner. Costume is allowed to be costume. The failure is listing it as karat because the front still looks yellow in warm store light. Tarnish on sterling is dirt and sulfur, not wear-through. It darkens the whole spoon or chain and polishes off. A copper edge does not. Leave tarnish until you can see the stamp, which is the same advice as the flatware guide, then decide.
A magnet, used on each part
A rare-earth magnet is a screen for steel. It is not a karat test. Gold does not stick. Sterling does not stick. Platinum does not stick. Stainless steel does. Some clasps, posts, and pin stems are steel even when the chain is not, because the mechanism needs a spring. Test the chain, the pendant, and the clasp as three objects. Write down which one grabbed.
A chain that sticks along its length is not a gold chain, whatever the color. A pendant that sticks is not a gold pendant. A clasp that sticks, on a chain that does not, is a steel clasp. That can be original, and it can be a repair. It is not, by itself, a reason to throw the chain back, and it is not a reason to buy the chain as gold.
What the magnet does not catch is the common problem. Brass, bronze, copper, aluminum, and a thick plating over any of them will not stick. A piece that falls off the magnet can still be plate. The marks guide says this in a paragraph. The aisle version is: pass the magnet, then look at the high points, then read the stamp. If there is no stamp and no wear-through and no stick, you still do not know the karat. You know it is not a steel chain. That is a smaller fact than the tag suggested.
White metals need the magnet most. Stainless, white gold, and rhodium-plated brass can look alike under bad light. The one that sticks is stainless or another magnetic metal. The ones that do not stick still have to be read. Non-magnetic is not a synonym for 14k.
Do not use a magnet on a mechanical watch if you care about the watch. Magnetizing a movement is a real way to make it run badly. Jewelry in this note means chains, pins, earrings, and rings. A watch is a different check, and the box is not the metal.
Weight, without a number you invent
Heft is how people talk themselves into a purchase. A hollow locket is light because it is hollow, not because it is fake. A gold-filled chain can feel heavy because the base metal is heavy. Solid does not mean heavy, and heavy does not mean solid. You learn weight by holding a piece you have already identified, then holding the question. You do not learn it from a sentence that says real gold feels heavier, because that sentence has no object in it.
A jeweler’s scale tells you grams. It does not tell you karat. Specific-gravity testing exists, and it is a bench test: weigh dry, weigh in water, compare with a known alloy. Hollow jewelry, stones, and a steel clasp make the number lie unless you already know how to account for them. If you do not run that test on ordinary days, do not start on the only locket in an estate box. An unmarked piece you cannot identify is a pass, or a question for a buyer who does this, not a density experiment in a parking lot.
Stones and a heavy clasp belong in the weight if you are going to say a weight at all. A buyer who melts will not pay you for the stone. A buyer who wants the jewel might. Say what you weighed, including what you did not remove. The karat guide is the rest of that conversation. This page will not print a gram price. Acid test kits and electronic testers can scar a piece or mislead you. If you do not already know how to use one, do not practice on the only clasp in the tray.
Stones, without a species you do not know
A stone is identified by someone who can defend the species, or it is described by color, cut, and what the loupe shows. Diamond, ruby, and emerald are claims. A thrift tag does not make them true. A family story does not make them true. The setting can be real gold around glass. Both facts can sit in one ring.
With a loupe, or a phone macro and patience, look for a mold line, which is a seam left in molded glass or plastic. Look for bubbles, which show up in glass more than in most gems. Look for foil or a painted back, common on old glass stones and a reason the color dies when the foil goes black. Look for chips at the girdle and a stone that is glued in a blob rather than held by prongs or a bezel that was finished cleanly. None of these proves a species. A mold line is enough to stop you calling it a diamond.
Thermal diamond testers are sold as pens. An older diamond tester can call moissanite a diamond, because it is reading heat, not identity. A pen that beeps is not a gemological report. If the piece is worth a laboratory, the laboratory is the answer. If it is not, the honest title is the color and the setting, and the metal stamp if you have one.
Pastes and rhinestones in costume jewelry were made to sparkle. They are not a failed diamond. Call them glass when you can see they are glass, and call them stones when you cannot. The costume guide is that market. Do not smuggle a red glass stone into a ruby search because the color is close. The buyer who searches ruby will be angry, and the buyer who searches red glass will not find you.
Count the stones. A missing one is the listing. Dark glue in an empty seat is the photo that belongs first, not last. Do not replace a stone and forget to say you did.
Pearls
A pearl’s check is the surface and the hole, not the clasp alone. A 14k clasp can close a strand of coated glass or plastic. The clasp is the mark. The beads are the question.
Nacre is the surface of a pearl, cultured or natural. Under a loupe it is slightly uneven. Light moves on it in a soft way, not as glitter painted on. Imitation pearls are beads with a coating. At the drill hole the coating chips, flakes, or shows a glass or plastic edge that is a different material from the skin. That flake is the useful photo. A perfectly smooth, glassy bead with a painted sheen and a flake at the hole is an imitation. Say so.
The tooth test is the old screen: nacre feels gritty against the edge of a tooth, glass feels slick. It is rough, it is not clean, and it can scratch a pearl, which is soft. Prefer the loupe. If you already did it and felt grit, you still do not know whether the pearl is cultured or natural. Those two are separated by a laboratory, not by a tooth and not by a phone. Cultured pearls are the ones you actually meet. Natural pearls are a different market. Do not upgrade a thrift strand to natural because the beads are old and a little off-round. Off-round is also how many cultured pearls look.
Knotting is a construction clue. A traditional strand is knotted between the beads, so one break does not send the rest across the floor. Unknotted beads on a nylon line are often later or costume. Knots can be redone. Fresh white thread on yellowed beads means the strand was restrung. That is a repair, and it is often a good one. Disclose it. A strand with a gap, a cracked bead, or a clasp that does not match the wear is incomplete in the way that matters.
Pearls get dull from hairspray, perfume, and a dry box. Dull is condition. It is not proof of age, and it is not proof of plastic. A harsh cleaner makes them worse. A soft damp cloth is as far as you go before you know what they are.
In the aisle
Work in a set order so you do not pay for the story. Light first. Stamp second, using the marks article, including the clasp and the back. Magnet third, each part. High points fourth, looking for a second color. Findings fifth, looking for a new clasp or an open ring. Stone or pearl last, and only as far as the loupe goes. If the stamp is missing, your price is an unmarked price. Estate-sale tags are someone else’s sentence. The flea-market check is the same habit on a small object, where a glance is expensive.
Then compare the object you can defend, not the object the tag named. Sold listings of a similar form, in similar wear, with the same honesty about stones. Fees come off whatever you get, at the marketplace’s current schedule, which this note will not print. A strand you cannot describe will come back, and the return costs the fee and the postage.
What a photo can settle
A photo can settle a complete stamp, a wear-through at a corner you put in the frame, a replaced clasp with a solder blob, a missing stone, a flake at a pearl’s drill hole, and a mold line in a glass stone if the macro is sharp. It can show a magnet hanging on a chain if you take that picture on purpose. It cannot weigh the piece, run a specific-gravity test, or tell cultured from natural. It cannot name a diamond. It cannot see the back of a locket you did not flip, or a clasp stamp you cropped out of the frame.
Worth can read a clear 14k, 925, or GF when the letters are sharp and complete. It cannot certify a stone, and it should not be asked to. Photograph the whole piece, then the stamp, then the flaw. The thrifting page is the aisle. The mark is one fact. The finding, the wear, and the bead are the rest. If those disagree with the tag, believe the ones you can show.