What Does 925 Mean on Silver?
A complete visual guide to silver purity — from 999 fine silver to 925 sterling and beyond.
The number stamped on silver — 925, 999, 800 — tells you the purity in parts per thousand. 925 sterling silver, the most common standard, is 92.5% pure silver alloyed with 7.5% copper for durability. 999 fine silver is nearly pure but too soft for everyday wear.
Volume visualization — silver vs. copper
Each droplet = same volume. Silver (10.5 g/cm³) is slightly denser than copper (8.96 g/cm³), so copper takes a little more space for the same weight.
999 Fine | 99.9 wt%
999 Fine
958 Britannia | 95.8 wt%
958 Britannia
925 Sterling | 92.5 wt%
925 Sterling
900 Coin | 90.0 wt%
900 Coin
830 Nordic | 83.0 wt%
830 Nordic
Silver purity at a glance
Each bar shows how much is pure silver (bright) vs. other metals (dark)
Every silver grade explained
Used for: Bullion bars, coins, high-end silverware
Worldwide
Used for: British hallmarked silverware, coins
UK, historically
Used for: Rings, necklaces, bracelets, cutlery
Worldwide
Used for: Older Scandinavian silverware, antiques
Norway, Sweden, Denmark (historically)
Used for: Old US coins, antique jewelry
USA (historically)
Why does sterling silver turn black?
It's the copper
Pure silver (999) barely tarnishes. But the 7.5% copper in sterling silver reacts with sulfur compounds in the air and on skin — forming silver sulfide, which is the black coating you see.
What accelerates it
Humidity, perfume, chlorine (pools), sweat, rubber bands, and wool all speed up tarnishing. Storing silver in airtight bags slows it significantly.
How to remove it
Baking soda + aluminum foil + hot water (electrochemical reaction), silver polishing cloth, or commercial silver polish all work well. The tarnish is surface-only — the silver underneath is fine.
925 vs 958 — direct comparison
Bottom line: 925 sterling is the global standard for a reason — it's the sweet spot between purity and durability. 958 is purer but too soft for most jewelry.
Volume visualization — silver vs. copper
Each droplet = same volume. Silver (10.5 g/cm³) is slightly denser than copper (8.96 g/cm³), so copper takes a little more space for the same weight.
999 Fine | 99.9 wt%
999 Fine
958 Britannia | 95.8 wt%
958 Britannia
925 Sterling | 92.5 wt%
925 Sterling
900 Coin | 90.0 wt%
900 Coin
830 Nordic | 83.0 wt%
830 Nordic
How to clean sterling silver at home
Tarnish looks alarming but is always surface-deep. Here are three proven methods ranked by effort and effectiveness.
- Line a bowl with aluminium foil, shiny side up
- Add boiling water and 1 tbsp baking soda per litre
- Place silver in bowl (touching the foil)
- Leave 5–10 minutes — tarnish transfers to foil
- Rinse and buff dry with a soft cloth
Avoid for pieces with glued stones or antique patina
- Mix a few drops of washing-up liquid in warm water
- Soak for 5 minutes to loosen grime
- Gently scrub with a soft toothbrush
- Rinse thoroughly with clean water
- Dry immediately with a lint-free cloth
Safe for almost all silver jewellery including set stones
- Use a two-layer polishing cloth (inner = cleaner, outer = buffer)
- Rub gently in straight strokes along the piece
- Do not use in circular motions — causes micro-scratches
- Use the outer buff cloth to restore final shine
- Wash hands after — the inner cloth contains compounds
Best for chains and flat surfaces; hard to reach crevices
Storing silver to prevent tarnish
Anti-tarnish bags
Zip-lock bags treated with anti-tarnish strips are the best value option. Remove air before sealing.
Lined jewellery boxes
Felt or velvet lining absorbs moisture. Avoid rubber or latex linings — they accelerate tarnishing.
Silica gel packets
Add a small desiccant sachet to your storage box. Reduces humidity, the main driver of silver tarnish.
Separate pieces
Store silver away from other metals and avoid contact with rubber bands, newspapers, and wool which all contain sulfur compounds.