US Mint · United States
The largest regular-issue US gold coin, minted from 1849 to 1933. Contains nearly one troy ounce of gold.
| Mass | 33.436 g |
| Troy Ounces | 0.9675 oz |
| Diameter | 34 mm |
| Thickness | 2.41 mm |
| Edge | reeded |
| Purity | 90% Au, 10% Cu |
| Fineness | 0.9 |
| Density | 17.2 g/cm³ |
| Face Value | 20 USD |
| Series | Pre-1933 Gold |
| First Minted | 1849 |
| Ping Frequency | 4,135 Hz |
Use these values to verify an authentic US $20 Double Eagle. 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.