What does COIN mean on jewelry?
Short answer
Coin silver: 900 silver (US).
A mark is a statement, not proof: it can be forged or struck on a plated piece. An assay confirms it (touchstone and acids, or X-ray fluorescence).
The stamp in detail
| Item | What the tables say |
|---|---|
| Stamp | COIN |
| Class | Fineness (purity) mark |
| Silver fineness | 900 parts per thousand (90 % silver) |
| Legal standard (silver 900) | United States (coin silver) |
| Source check | Checked against the sources listed below |
What is COIN worth by weight?
Every gram of a piece stamped COIN holds 0.9 g of fine silver, if the stamp is accurate. Multiply that by the spot price of silver to get the melt value. It is the floor, what the metal is worth if melted, not what a buyer will pay and not an appraisal.
Example, clearly not live: 10 g at the example price of $51.87 per troy ounce (snapshot of 2026-11-10) is $15.01. The working: 10 g → 900 / 1000 → 10 g × 0.9 → 51.871 USD/ozt ÷ 31.1034768 g/ozt → 9 g × 1.6677 USD/g.
Melt value calculator for COIN
Enter a weight and a stamp to see the sum.
Today's spot price: LBMA precious metal prices, Kitco live gold or your own dealer's quote. This page never contacts a price service.
What COIN can be mistaken for
Pieces that look like silver and are not:
- silver plate (EPNS)
- alpaca, nickel silver
- white gold and platinum
What a stamp cannot settle: Silver, white gold or platinum without marks: white colour does not tell them apart.
What settles it:
- Jeweller: acids or X-ray fluorescence.
Related stamps
Other ways the same fineness is stamped: 900.
Frequently asked
What does COIN mean on jewelry?
Coin silver: 900 silver (US).
Does COIN mean the piece is solid silver?
It means the piece is stamped as silver, 900 parts per thousand. A mark is a statement, not proof: it can be forged or struck on a plated piece. An assay confirms it (touchstone and acids, or X-ray fluorescence).
How much fine silver is in a piece stamped COIN?
0.9 g of fine silver per gram of metal, if the stamp is accurate. Melt value is that weight times the spot price. It is not an appraisal.
Sources
All sources are listed with the method on the sources page.