GoldToPrice guide · Updated 2026-10-11
How to Read Gold Hallmarks: 375, 585, 750 and 916
Read the entire mark, not just a number: 750 describes fineness, while GP or GF changes the construction. A stamp alone cannot establish authenticity or resale value.
Find and record the marks without damaging the piece
Use bright indirect light and a loupe or a phone's close-focus camera. On rings, marks are often inside the band; on chains, check the clasp and the small adjoining tab. Pendants may be marked on the reverse or bail. Earrings can have tiny marks on a post or fastening rather than the decorative section. Photograph several angles because a worn stamp can make a 3 resemble an 8 or a 6 resemble a 9. Do not polish aggressively to reveal a mark: removing surface material can damage an antique or reduce legibility. Keep the item and its clasp associated, but remember that a replacement clasp can carry a different purity from the chain. Record exactly what is visible before translating it into a karat assumption.
Translate the common fineness numbers
A millesimal mark indicates parts of precious metal per thousand. In gold contexts, 375 means 37.5%, 750 means 75% and 875 means 87.5%. The familiar 585 mark means 58.5%; it is associated with 14K jewelry, though nominal fourteen-karat math gives about 58.333%. Likewise 916 and the nominal twenty-two-karat fraction differ slightly. A 999 or 9999 marking describes a very high fineness rather than literally unlimited purity. Interpret the number with the object and other marks: 925 is commonly sterling silver, not a lower standard of gold. A gold-colored 925 ring may be plated silver. A single isolated number can also be a model or inventory number, so do not convert every three-digit stamp into a gold valuation without context.
Recognize the British hallmark as a group of marks
A UK hallmark is more than a fineness stamp. Its compulsory elements include a sponsor's mark, a metal and fineness mark, and an assay office mark. A date letter is optional in modern hallmarking, so its absence does not automatically identify a fake. The familiar assay-office symbols can help identify where a piece was tested, but shapes and historic conventions must be interpreted carefully. Official guidance gives the accepted standards and exemptions. For gold, 375 is a recognized standard; weight exemptions and rules for mixed constructions also exist. A seller's bare 9ct label is not the same evidence as a complete legally applicable hallmark. Use official assay-office information when identifying an old mark instead of relying only on a generic image chart or a marketplace seller's guess.
Read American karat marks and qualifying words together
American jewelry commonly carries marks such as 10K, 14K, 18K or a manufacturer's trademark. These are not the same system as an independent British assay hallmark. FTC guidance addresses accurate descriptions and material claims, so look for words that qualify the stated fineness or construction. A marking like 14K GP indicates gold plating; 14K GF indicates gold-filled construction. A seller should not describe the whole item as solid fourteen-karat gold simply because its surface layer has that purity. Familiar retail conventions do not replace current legal guidance. For a purchase, get the material description in the receipt, including whether it is solid alloy, hollow, plated or filled. Hollow solid-gold jewelry is an alloy shell, not necessarily plating, but its durability and net weight differ from a solid-section piece.
Understand what a hallmark cannot tell you
A genuine hallmark gives useful evidence about the tested metal under its applicable system, but it does not price the item. It cannot tell you current stone quality, brand demand, repair costs or sentimental value. Marks can also be copied, added to misleading constructions or attached on a component that does not represent the rest of the piece. A clasp may be replaced; a ring may have been resized with different solder; a chain may contain several metals. That is why a gold buyer can legitimately request testing even when marks are present. Conversely, the absence of a visible mark is not proof that an item contains no gold: wear, age, exemptions and repairs may explain it. Treat the mark as one part of identification rather than the entire conclusion.
Know the limits of home tests
A magnet can identify some strongly magnetic components but cannot certify gold. Many non-gold metals are nonmagnetic, while a genuine gold chain may have a steel spring in its clasp. Color, heft and a ceramic streak are also not reliable standalone assays and may damage a piece. Acid tests require care and can mark an item; they are not a good first step on valuable jewelry with possible resale demand. Density can be informative for a simple solid object but becomes difficult with stones, hollow sections and mixed metals. Professional X-ray fluorescence examines composition at the measured area and also has limitations, especially for layered items. Ask the tester what method is appropriate to the construction and how confidently the result describes the whole item, not just the surface.
Connect the mark to a transparent valuation
After identifying the likely purity, weigh the net gold-bearing metal and calculate a spot reference. For an illustrative 10 g object with a genuine 750 alloy, fine-gold weight is 7.5 g. If a stone or non-gold part accounts for 2 g of that gross weight, the metal weight is 8 g and fine-gold content is 6 g instead. Those are very different calculations, even though the hallmark is unchanged. Use our purity tables to compare common grades, then ask the buyer for its accepted weight and tested fineness. A buyer's actual cash offer can be below the metal reference because of costs and margin. Do not describe a percentage as universal; compare measured, written net offers for the same item and quote time.
Preserve provenance and get specialist help when needed
Keep photographs of marks, receipts, certificates and any identification work. For antique pieces, maker's marks and date information can be as important as fineness, and polishing or destructive testing can remove useful evidence. A specialist may recognize construction, period and maker details that a generic cash-for-gold desk does not value. For investment bars and coins, use the refiner's or mint's specifications and authenticity process rather than applying jewelry rules automatically. If a listing or hallmark interpretation remains ambiguous, ask for clarification before buying. The cost of a professional examination may be sensible when the item is valuable or a disputed mark changes the transaction. Our tables explain metal math; they do not certify objects or replace an assay office, an experienced jeweler or an independent appraisal.
Put the explanation into today's numbers
Gold · USD · per troy ounce · spot value
$4,186.10
-0.20% over 24h
Last quote
With the current reference, fine gold is $134.59 per gram. An illustrative 10 g 18K item has a melt value of $1,009.40; a hypothetical 80% buyer payout is $807.52. The payout is an assumption, not an observed offer.
Frequently Asked Questions
What does a 750 gold hallmark mean?+
It describes a nominal fineness of 750 parts gold per thousand, or 75% gold, commonly called 18K.
Is a missing date letter evidence of a fake UK hallmark?+
Not by itself. Date letters are optional in modern UK hallmarking; assess the full marks and applicable rules.
Can a magnet prove that jewelry is gold?+
No. Non-gold metals can be nonmagnetic, and genuine jewelry may include a magnetic steel spring or another component.
Sources & editorial note
GoldToPrice publishes this educational reference. No individual expert credential or independent review is claimed. Calculations use our disclosed data methodology; official rules and product terms take precedence. Report corrections at hello@metalflowapi.com.