tools · identification
hallmark decoder.
that tiny number stamped inside a ring or clasp tells you the metal and how pure it is. type it in to decode it: gold, silver, platinum, and the plating marks that only look like solid gold.
gold
375
solid9K gold
37.5% gold
common in the UK and Europe. durable and affordable, but under half gold. the rest is alloy.
417
solid10K gold
41.7% gold
the minimum karat that can legally be called 'gold' in the united states. hard-wearing, popular for everyday and men's pieces.
585
solid14K gold
58.5% gold
the workhorse of us fine jewelry, balancing gold content, durability, and price. sometimes stamped 583 on older pieces.
750
solid18K gold
75% gold
the luxury standard. rich colour and high gold content, softer than 14k. the default for european and designer fine jewelry.
875
solid21K gold
87.5% gold
common across the middle east and south asia, where higher gold content is prized for bridal and investment pieces.
916
solid22K gold
91.6% gold
traditional for indian and asian gold jewelry. deep yellow and very soft, usually reserved for pieces worn occasionally.
999
solid24K gold
99.9% gold
pure gold. too soft for most jewelry, so mostly bullion, bars, and coins. a 990 stamp is 24k chinese 'chuk kam' gold.
333
solid8K gold
33.3% gold
a low-karat german and central-european standard. legal to call gold in parts of europe, but not in the us or uk.
silver
925
solidsterling silver
92.5% silver
the global standard for silver jewelry. 92.5% silver with 7.5% alloy (usually copper) for strength. also written 'sterling'.
800
solid800 silver
80% silver
a continental european standard, common on older german, italian, and swiss pieces. slightly less silver than sterling.
835
solid835 silver
83.5% silver
a european silver standard often seen on vintage german and dutch jewelry and flatware.
900
solidcoin silver
90% silver
historically made from melted coins. common on antique american and european pieces from before sterling was standard.
958
solidbritannia silver
95.8% silver
a higher purity than sterling, used for premium british silver. softer, so less common in everyday jewelry.
999
solidfine silver
99.9% silver
nearly pure silver. bright and soft, used for bullion, some artisan pieces, and enamel work. note: 999 also means 24k for gold.
platinum
950
solid950 platinum
95% platinum
the standard for platinum fine jewelry. dense, hypoallergenic, and naturally white, with no rhodium plating needed. often stamped 'plat'.
900
solid900 platinum
90% platinum
90% platinum, common in vintage and some japanese pieces. note: 900 also appears as a silver mark, so check the 'pt' prefix.
850
solid850 platinum
85% platinum
the lowest fineness usually marked as platinum. seen on some settings and chains where extra strength is wanted.
palladium
950
solid950 palladium
95% palladium
a lighter, naturally white platinum-group metal. hallmarked pd950 or pd500. an affordable white-metal alternative to platinum.
500
solid500 palladium
50% palladium
an entry-level palladium standard, half palladium and half alloy. less common than pd950, seen on some lighter or lower-cost white-metal pieces.
plated / filled
GP
platedgold plated
base metal + thin gold layer
a microscopic layer of gold over a base metal. almost no gold weight and no scrap value. 'gep' means gold electroplated.
GF
platedgold filled
5% gold by weight, bonded
a thick, mechanically bonded gold layer, far more durable than plating. the mark shows the fraction and karat, e.g. '1/20 14K GF'. still not solid gold.
RGP
platedrolled gold plate
thin bonded gold layer
a thinner cousin of gold filled: a bonded gold layer, but less of it. common on vintage watches and costume pieces.
HGE
platedheavy gold electroplate
base metal + electroplated gold
electroplated gold, marketed as 'heavy'. despite an '18K HGE' stamp, the piece is plated base metal, not solid gold.
vermeil
platedgold vermeil
sterling silver + thick gold plating
sterling silver with a thick gold plate (at least 2.5 microns, 10k+). the best of the plated options, with solid silver underneath, so it has real melt value.
EPNS
platedsilver plated
base metal + thin silver layer
electroplated nickel silver: a thin silver coat over base metal, no sterling content. 'ep' or 'a1' mean the same. no scrap value.
where to look
how to find and read the stamp.
hallmarks hide where they won't interrupt the design: the inside of a ring band, the flat of a clasp, the post or back of an earring, the tag near a necklace clasp. a loupe or your phone camera on macro helps, since they're often smaller than a grain of rice.
you'll usually find one of two systems. a karat number (10K, 14K, 18K) is the us and asian convention. a three-digit fineness mark (417, 585, 750) is the european one. both describe the same thing: how much of the metal is actually gold.
a maker's mark or country hallmark sometimes sits alongside it. those identify who made the piece and where, useful for dating and provenance, but it's the fineness mark that tells you the value.
is it real?
four checks before you trust a stamp.
a mark is a strong signal, not a guarantee. stamps can be faked or worn away, so these quick checks back it up.
01
the magnet test.
gold, silver, and platinum are not magnetic. if a piece pulls to a strong magnet, the core is base metal, so it's plated at best.
02
read the whole stamp.
GP, GF, HGE, RGP, and EP all mean plated or filled, not solid. a lone karat mark with no plating letters is the reassuring one.
03
look for wear.
plating wears through at edges and high-contact points, showing a different metal beneath. solid gold wears evenly and stays the same colour throughout.
04
confirm it properly.
for money-on-the-line certainty, a jeweler's acid test or an XRF scan reads the exact karat in seconds. worth it before you buy or sell.
once you know the karat, the gold price calculator turns it into a melt value from the live spot price.
questions
stamps, decoded.
selling what you make?
the stamp proves it's real. the photo makes it sell.
bling ai turns an iphone photo of your piece into a campaign-ready shot in about a minute. free to start.
