KaratGuide

বিজ্ঞাপন

Ag

রুপায় 925 মানে কী?

রুপার বিশুদ্ধতার মাত্রা এবং হলমার্কের ভিজুয়াল গাইড।

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

Pure silver (Ag)
Copper (Cu) — by volume

Silver purity at a glance

Each bar shows how much is pure silver (bright) vs. other metals (dark)

99.9%
999
Fine
95.8%
958
Britannia
Most common
7.5%
92.5%
925
Sterling
10.0%
90.0%
900
Coin
17.0%
83.0%
830
Continental
Pure Silver
Other metals (copper, nickel…)

Every silver grade explained

Fine Silver
Hallmark: 999
Silver purity 99.9%
Other metals: 0.1%

Used for: Bullion coins, electroplating, industrial

📍 Global standard

✓ Purest form available
✗ Too soft for most jewelry
Britannia Silver
Hallmark: 958
Silver purity 95.8%
Other metals: 4.2%

Used for: UK silverware, antique pieces

📍 Mainly UK

✓ Very high purity
✗ Soft, mainly UK
Most common worldwide
Sterling Silver
Hallmark: 925
Silver purity 92.5%
Other metals: 7.5%

Used for: Rings, chains, earrings, cutlery

📍 Global — the world standard

✓ Best durability-purity balance
✗ Tarnishes over time
Coin Silver
Hallmark: 900
Silver purity 90.0%
Other metals: 10.0%

Used for: Historical coins, US antiques

📍 USA (historical)

✓ Harder than sterling
✗ Less pure, mainly historical
Continental Silver
Hallmark: 830
Silver purity 83.0%
Other metals: 17.0%

Used for: Older Scandinavian silverware

📍 Scandinavia (historical)

✓ Very durable
✗ Low purity, rare today

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

Property
Sterling Silver — 925
Britannia Silver — 958
Silver content
92.5%
95.8%
Other metals
7.5% (usually copper)
4.2% (usually copper)
Hardness
✓ Harder, more scratch-resistant
✗ Softer, dents more easily
Tarnish resistance
Moderate
Slightly better (less copper)
Availability
✓ Widely available worldwide
✗ Rare — mainly UK silverware
Price
More affordable
Slightly more expensive
Best for
All jewelry — rings, chains, earrings
Silverware, antique items, UK hallmarked pieces
Stamp
925 or "Sterling"
958 or Britannia mark

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

Pure silver (Ag)
Copper (Cu) — by volume

বিজ্ঞাপন

বিজ্ঞাপন