Grades & Purity

Purity is the single biggest variable in your precious-metal payout. A 24K bangle and a 10K class ring from the same drawer can differ by 2.4× per gram — same shape, same weight, wildly different paychecks. A 12-gram 14K rope chain at $2,500/toz gold spot is roughly $570 in your pocket; the same 12 grams in 10K is closer to $400. That sort is worth $170 in five seconds.

This page is the field guide to every stamp on jewelry, silverware, and coins — gold karats, silver fineness conventions, hallmark decoding, and the platinum/palladium markings most sellers miss. Cross-reference any piece against the tables below before you walk into a buyer; the refining and selling page covers what to do once you know what you have.

Gold karat chart — what each mark means

Karat is just a fraction. Pure gold is 24 parts out of 24, so 18K means 18 parts gold + 6 parts alloy = 75% gold. Every karat number you'll see on jewelry is some variation on that fraction — and the metric world expresses the same purity as a three-digit "fineness" number (750 instead of 18K, 585 instead of 14K). Same metal, same purity, two notation systems.

The math at a refiner is gross weight × purity × spot × payout factor. Worked example: a 14K ring, 8 grams gross, gold at $2,500/toz. Convert grams to troy ounces (8 ÷ 31.1035 = 0.257 toz), multiply by purity (0.257 × 0.585 = 0.150 toz pure gold), multiply by spot ($0.150 × $2,500 = $376 melt), then apply the factor (0.55–0.58 → roughly $207–$218 cash). The refresher on grams, troy ounces, and pennyweights lives on the basics page.

The payout factor isn't a cheat — it covers the refiner's assay, melt, and dealer margin. Lower karats earn slightly worse factors because refining cost is per-piece, not per-gram (more on that in the last section).

Silver fineness — sterling vs fine vs coin silver

Silver has three conventions you'll see in the wild. Sterling is .925 (92.5% silver, 7.5% copper for hardness) — the dominant standard for US/UK silverware and jewelry. Fine silver is .999, almost exclusively used in bullion bars and rounds because pure silver is too soft for utensils. Coin silver is .900, the alloy in pre-1965 US dimes, quarters, and halves — "junk silver" to dealers. Britain's older Britannia standard runs .958, German pre-WWII flatware sometimes .800, and Mexican silver varies .720–.925 depending on era.

Sterling silverware is the most overlooked hidden value in the average house — a single weighted candlestick can run 200+ grams of sterling, which at $30/toz silver clears $170. Pull the live silver price to math out a candidate piece.

Reading hallmarks — what the stamps mean

Hallmarks are tiny stamps tucked inside ring bands, on the underside of clasps, behind earring posts, and near the handle joint on flatware. A 10× jeweler's loupe makes them readable; a phone camera in macro mode works in a pinch. Most pieces carry two or three marks: a fineness or karat number, a maker's mark, and on European pieces a country/assay-office stamp.

Here's the decoder ring:

• Numbers (375, 585, 750, 916, 925, 999) → fineness in parts-per-thousand. 925 = sterling, 750 = 18K, 999 = fine silver or 24K depending on the metal context.
• Letters (10K, 14K, 18K, K22, KP) → karat. "KP" means "karat plumb" (exactly that karat, not under) and is a legitimate purity mark.
• Country marks → anchor + lion = UK Birmingham assay; eagle's head = France; "800" or "835" with a crescent + crown = pre-WWII Germany; eagle assay marks = Mexico; Cyrillic kokoshnik = Russia. The UK assay offices page has the canonical British symbols if you find a piece you can't place.
• Maker's marks → initials, tiny logos, named brands (Tiffany, Cartier, Georg Jensen). High-value pieces almost always have one alongside the purity stamp.
• "GP", "GF", "GE", "EP" prefixes → plated or filled. NOT solid. Worth a tiny fraction of solid value (more on that next).

Worked decode: a ring stamped 750 / G&Co / anchor + lion is 18K gold made by maker G&Co, assayed in Birmingham UK. At 8 grams and $2,500/toz, that's $482 melt × 70% factor = **$337 cash** at a refiner. The same ring sold through a luxury consignor with a real maker pedigree could pay 2–3× that — see refining and selling for venue choice.

If a piece has no hallmark, don't assume it's base. Pre-1900 American jewelry was often unmarked, and handmade artisan pieces sometimes skip stamps. Test before assuming.

Plated and filled vs solid — the gotcha

This is where the most disappointment happens. A piece can look indistinguishable from solid gold and still be worth almost nothing if it's plated. The prefix decoder:

• GP (gold plated) → microns-thin layer over a base metal. Negligible value.
• GF (gold filled) → mechanically bonded layer, must be 1/20th by weight gold (so "1/20 14K GF" = 5% by weight 14K gold). Some refiners will buy gold-fill in volume; one-off pieces are usually rejected.
• GE / GEP (gold electroplate) → even thinner than GP. No scrap value.
• HGE / HGP (heavy gold electroplate / rolled gold plate) → marketing terms. Still negligible.
• EP / EPNS / EPBM (electroplated, electroplated nickel silver, electroplated Britannia metal) → silver-plate equivalents. Base nickel or copper underneath; no silver scrap value.
• A1 / Sheffield / Silverplate → silver-plated flatware. Pretty, mostly worthless as scrap.
• Vermeil / silver-gilt → sterling silver with a thin gold layer. Sells as silver, not gold.

The fast field tests:

1. Magnet test. Solid gold, silver, and platinum are all non-magnetic. Magnet sticks → plated steel. Free, decisive on the obvious fakes.
2. Acid test. A $15 kit of nitric/HCl reveals real karat — a single bead on a discrete inside surface, read the color reaction.
3. Buyer XRF scan. Any serious refiner or coin dealer has an X-ray fluorescence gun that reads alloy non-destructively. Insist on this for high-value pieces. The unit-conversion refresher helps if the buyer reports grams or pennyweights and you're tracking dollars.

Vermeil is trickiest — there really is silver under the gold flash, so you get sterling melt value (real money on a heavy piece) but nothing for the gold layer.

Platinum and palladium markings

Platinum-group metals (PGMs) are uncommon in scrap jewelry but pay extremely well when you do find them. Markings:

• Pt950, 950 Plat, PLAT → 95% platinum. The standard for US/UK platinum jewelry.
• Pt900, 900 Plat → 90% platinum, common in Japanese pieces.
• Pt1000, Pt999 → fine/bullion platinum.
• IridPlat → 90% platinum + 10% iridium, common in vintage American platinum.
• Pd950 → 95% palladium, used in modern white-jewelry alloys.
• Pd500 → 50% palladium, sometimes blended into white-gold alloys.

Two things to remember. Bright white-metal jewelry that looks "platinum-ish" is more often white gold (gold alloyed with palladium, nickel, or silver) than real platinum — check for a Pt or Pd stamp first. And confirm your refiner handles PGMs before sending; some buyers only deal in gold and silver and subcontract platinum to a third party at a worse rate.

The dirty secret of the PGM market: most refined platinum, palladium, and rhodium volume in the US doesn't come from jewelry at all — it comes from catalytic converters cut out of scrapped cars. The auto-scrap recycling page covers cat-converter pricing.

Why purity scales the payout (and when it doesn't)

The first-order math is linear. A 10K piece weighs the same per gram as a 14K piece but contains ~30% less gold (41.7% vs 58.5%), so it pays ~30% less. Payout = purity × weight × spot × factor, and three of those four are facts about the piece — the factor is the only knob the refiner controls.

The factor itself shrinks slightly on lower karats and small lots, because refining cost is per-piece, not per-gram. A refiner eats roughly the same sort + assay + melt cost on a $50 lot as on a $5,000 lot, so fixed cost takes a bigger percentage bite from the small lot. A 50-gram bag of 10K class rings quotes a worse factor than a single 50-gram 18K bracelet — same gross weight, but the refiner has to handle 30+ pieces vs. one. For deeper venue economics — refiner vs. coin shop vs. luxury consignor — see refining and selling, and check live gold spot before quoting yourself a number.

Frequently asked questions