Fineness expresses the purity of a precious metal as parts per thousand. A coin marked ".999 fine" contains 999 parts pure metal per 1,000 parts total.
Common Fineness Levels
| Marking | Purity | Common Use |
|---|---|---|
| .999 | 99.9% | Standard silver bullion, some gold bars |
| .9999 | 99.99% | Canadian Maple Leafs, premium bars |
| .99999 | 99.999% | Specialty coins (Royal Canadian Mint) |
| .995 | 99.5% | Minimum for gold investment grade |
| .9167 | 91.67% | 22K gold (American Eagle, Krugerrand) |
| .900 | 90% | Pre-1965 U.S. silver coins |
Why Purity Matters
- Higher purity = more precious metal per unit of weight
- Different products require different minimum purities for various programs
- Ultra-high purity (.9999+) metals are softer and more susceptible to scratching