585 stamped on gold means the metal is 585 parts per thousand pure gold, or 58.5%, and it is the number used for 14 karat gold. The UK Hallmarking Act sets 14 carat at "585 parts per thousand" (Hallmarking Act 1973), and GIA lists 14K as "583 or 585" (GIA), because 14 parts of gold out of 24 works out to 58.3%.
What do the numbers stamped on gold mean?
A three-digit stamp is the gold content in parts per thousand. A karat stamp counts the same thing in 24ths. These are the marks you are most likely to find inside a band or on a clasp:
| Number stamp | Karat | Pure gold |
|---|---|---|
| 375 | 9K | 37.5% |
| 417 | 10K | 41.7% |
| 583 or 585 | 14K | 58.3% to 58.5% |
| 750 | 18K | 75% |
| 916 | 22K | 91.6% |
| 999 | 24K | 99.9% |
The 375, 585, 750, 916 and 999 marks are the standard marks in Schedule 2 of the Hallmarking Act; GIA gives 10K as 417 and 14K as "583 or 585".
Is 585 gold the same as 14k gold?
Yes. 583 is 14/24 rounded, and 585 is the standard fineness the hallmarking system uses for 14 carat. Both stamps describe 14 karat gold, and a 585 piece carries slightly more gold than the bare 14/24 figure.
What do 14K, 14KT and 14 K. mean?
They all mean 14 karat. The FTC's jewelry guides give "14 Karat Gold," "14 K. Gold" and "14 Kt. Gold" as acceptable markings, and say a gold alloy may be called "Gold" only when the word is "immediately preceded by a correct designation of the karat fineness of the alloy" (16 CFR 23.3). A piece stamped just "Gold", with no karat, is not making a karat claim you can rely on.
What do GF, R.G.P. and G.E.P. mean on gold?
They mean the gold is a layer on another metal, not gold all the way through. Under the same FTC rule:
- Gold filled (GF): allowed when the gold layer "constitutes at least 1/20th of the weight of the metal in the entire article".
- Rolled gold plate (R.G.P.): a thinner mechanically applied layer of at least 1/40th of the weight, marked for example "14K. R.G.P."
- Gold electroplate (G.E.P.): a layer applied by electrolysis with "a minimum thickness throughout equivalent to 0.175 microns" of fine gold, marked for example "12K G.E.P." Heavy gold electroplate needs two and one half microns.
So "14K GF" describes a 14 karat layer, not a 14 karat piece. Plated and filled pieces are valued for their gold layer only, which is a small fraction of their weight.
How accurate does a gold stamp have to be?
Very. Under the National Gold and Silver Stamping Act, the gold in a marked article "shall not be less by more than three one-thousandth parts than the fineness indicated by the mark" when the part tested contains no solder (15 U.S.C. 295). Counting the solder, the whole piece may fall short by no more than seven parts per thousand, the same tolerances the FTC repeats in its guides.
Does a karat stamp prove the gold is real?
It is a starting point, not proof. The law expects a maker's mark beside a quality mark: anyone applying a gold quality mark "shall apply to the article the trademark or name of such person" (the National Stamping Act, quoted in 16 CFR 23.10). A karat stamp with no maker's mark, a stamp next to GF or G.E.P., or a stamp on a piece that wears through to a different color is a reason to have it tested. When you bring gold to our counter, we test each piece in front of you before we weigh it.
What is my 585 gold worth?
Multiply the weight in grams by 0.585, divide by 31.10348 (the grams in a troy ounce, per NIST) and multiply by the day's gold price per troy ounce. As an example, at a gold price of $4,000 an ounce, 10 grams of 585 gold holds 5.85 grams of pure gold, worth about $752 at that price. Our gold value calculator does the math with today's live price for every karat, and our guide to how buyers work out the price explains why an offer is below that figure.
Have it tested in Paramus
Bring your pieces and a photo ID to our counter inside The Jewelry Center on Route 4. We test the karat and weigh each piece in front of you, then offer cash or credit toward a new piece; see sell gold and trade-in or book an evaluation.
Prestige Diamonds NJ
327 E State Route 4, Paramus, NJ 07652
(201) 488-4280
