Under current United States FTC guidance, sterling silver is at least 92.5% silver. The remaining alloy, finish, solder, and construction still need disclosure, and normal tarnish is not proof that a piece is fake.

A plain-language guide to the United States sterling threshold, the limits of a 925 mark, normal tarnish, and why polishing and finish details affect care.

What this guide covers

Read 925 or sterling as a fineness claim, not a complete assay.
Separate normal tarnish from dirt, intentional oxidation, plating wear, and active corrosion.
Choose care from the whole piece before polishing or using a dip.

925 tells one part of the story

Material boundary
A 925 or sterling mark states a silver-fineness claim in the United States. It does not identify every alloying metal, solder, plating, coating, stone, adhesive, or prior repair.

Identify the surface before choosing care

Ordinary tarnish

Silver and its alloying metals can react with the environment. Tarnish may be normal, but it does not authenticate the piece.

Plated or intentionally oxidized finish

A standard polish can remove or alter the surface, so the finish must be identified first.

Stone-set or repaired piece

Stones, adhesives, solder, and prior work can narrow which cleaners or polishing methods are suitable.

Read, inspect, then care

1 — Read the mark and disclosure
Note the fineness claim, maker or responsibility mark when present, finish, stones, and any repair information.
2 — Inspect the surface
Look for tarnish, plating wear, intentional darkening, loose stones, damaged joins, or active corrosion.
3 — Choose the least aggressive suitable care
Remember that polishing removes a small amount of surface material and can soften detail over time.
4 — Escalate uncertainty
Ask a qualified jeweler before treating an antique, plated, oxidized, stone-set, adhesive-set, or valuable piece.

Sterling silver questions

Does 925 mean the rest is always copper?

No. Copper is common, but the 925 mark alone does not identify the exact alloy balance, coating, solder, or construction.

Does tarnish mean the piece is fake?

No. Tarnish can be normal. It also does not prove authenticity, so read the disclosure and use appropriate testing when the decision matters.

Is frequent polishing harmless?

No. Polishing removes a small amount of surface material, and aggressive or repeated polishing can soften detail or alter a finish.

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