Monnaie de Paris · France
Gold coin of Emperor Napoleon III struck during the Second Empire. Contains 5.81g fine gold. Both laureate and bare head varieties exist.
| Mass | 6.452 g |
| Troy Ounces | 0.1867 oz |
| Diameter | 21.1 mm |
| Thickness | 1.31 mm |
| Edge | reeded |
| Purity | 90% Gold, 10% Copper |
| Fineness | 0.9 |
| Density | 17.2 g/cm³ |
| Face Value | 20 FRF |
| Series | Napoleon |
| First Minted | 1852 |
| Ping Frequency | 5,547 Hz |
Use these values to verify an authentic French Gold Napoleon III 20 Francs. All tests can be performed with a digital scale, calipers, and the EON ping tester.
Use a 0.01g digital scale. Calibrate first with a known object (a €2 coin = 8.50g).
Use plastic calipers (not steel — avoid scratching). Or use the camera tool with a bank card as reference (ISO 7810: 85.60mm × 53.98mm).
Balance the coin on your fingertip and tap the edge with a pencil or plastic pen. Use the Ping Tester to analyse the ring.