What does 925 mean on jewelry? Sterling silver, coin silver and the FTC line

On jewelry, 925 means 925 parts per thousand pure silver, or 92.5 percent. That is the sterling silver standard. Under the Federal Trade Commission's Jewelry Guides, the words "sterling," "sterling silver" and "solid silver" may be used only on a product that is at least 925/1,000ths pure silver. The rest of the metal, usually copper, is there for strength. Everything below is read from the eCFR on October 24, 2026.

What the number actually says

Fine silver is about 99.9 percent pure and relatively soft, according to Wikipedia's entry on sterling silver. Alloying it with copper makes it hard enough to hold a shape as a ring or a clasp. Sterling is that compromise: 92.5 percent silver and 7.5 percent other metals, usually copper. The same entry gives the sterling standard a minimum millesimal fineness of 925, which is the number you see stamped inside a band or on the back of a pendant.

Other grades exist. Wikipedia lists Britannia silver at 95.8 percent and Argentium sterling at 93.6 percent or 96 percent, and it describes coin silver as .900 fine, widely used in pre-1964 United States coinage. Those are separate names for separate purity levels.

What the FTC says you may call it

The Guides apply to what the FTC calls "industry products," which includes jewelry. Section 23.5 is the silver section. It lists markings that may be misleading, and the thresholds are plain.

The words "solid silver," "Sterling Silver," "Sterling" or the abbreviation "Ster." are misleading unless the product is at least 925/1,000ths pure silver. "Coin" or "coin silver" needs at least 900/1,000ths. The bare word "silver" needs an equally conspicuous, accurate fineness number immediately in front of it, and the Guides' own example is "750 silver."

That last rule catches more listings than the first two. A product page that says "silver ring" with no number is exactly the use the section flags. A seller who wants to say plain "silver" has to say how much.

Plated is not sterling

Section 23.5 also covers coatings. If a product is not silver all the way through but has a silver surface, the word "silver" has to be qualified to show the piece is only coated. A seller may call a product plated or coated with silver only if all significant surfaces carry a coating of reasonable durability.

The strictest rule sits in a note. The National Stamping Act, 15 U.S.C. 297(a), provides that silver plated articles shall not be stamped, branded, engraved or imprinted with the word "sterling" or the word "coin," alone or with other words or marks. So a plated piece carrying the word sterling is a problem on its face, not a gray area.

If you want the same treatment for gold, our explainer on gold plated, gold filled and vermeil reads the neighboring sections, including the vermeil rule that requires a sterling base.

Tolerance: how close counts

Real metal is never exactly 92.5 percent. A footnote to section 23.5 says that under the National Stamping Act, sterling silver articles or parts that contain no solder have a permissible tolerance of four parts per thousand. If the part tested contains solder, the tolerance is ten parts per thousand. The footnote points readers to 15 U.S.C. 294 and following for the full text.

So the legal floor for an unsoldered sterling item is not a flat 925. The Act allows a four point tolerance. That is a detail for assay offices and importers, not a reason to doubt a stamp, but it explains why you will not find lab results that match 92.5 exactly.

What the stamp does not tell you

Here is the catch. The section regulates claims. It does not say that a stamp proves anything. In the text we read, section 23.5 does not itself require a 925 mark, and nothing in it tells you who applied the stamp. A mark from an unnamed factory is a claim by the seller, and the Guides treat it that way.

The Guides are also advice, not a statute. Section 23.0 says conduct inconsistent with them may bring corrective action under the FTC Act, if the Commission has reason to believe the behavior falls within conduct declared unlawful. They are the yardstick the agency uses, and the National Stamping Act sits underneath for the plated-sterling stamp.

Tarnish, and why it is not a purity test

Sterling tarnishes. Wikipedia notes it is prone to tarnishing, and that elements other than copper, including germanium, zinc, platinum, silicon and boron, can be used in alloys to reduce it. Tarnish is a reaction on the surface. It does not mean a piece is fake, and a piece that never tarnishes is not proof that it is better silver. Polishing away the film is a surface job.

One related note for parents. The Consumer Product Safety Commission's lead rule for children's products, 16 CFR 1500.91, lists gold of at least 10 karat and sterling silver of at least 925/1000 among the metals that do not exceed the lead limits, as long as no lead is intentionally added. That exemption names sterling by the same number, which is one more place the 925 line carries legal weight.

Our take

Read the whole description, not the shine. Sterling or 925 plus a maker's mark is a defensible claim. The bare word "silver" without a number, or "silver tone," is a color. A plated piece stamped sterling runs against the National Stamping Act on its face, and a listing that will not say which one it is has told you enough. We would buy from a seller who names the standard and skip one who hides behind the word silver.