Coin Pinger
Acoustic bullion authentication — free, private, on-device
Authenticity guide
Is my Silver American Eagle 1 oz real?
Four checks — weight, size, magnet, and the ring — catch the overwhelming majority of fakes, because a counterfeit can fake the look but not the physics. Every threshold below is computed from the official spec and our acoustic model.
The 60-second checklist
| Check | Genuine Silver American Eagle 1 oz | Red flag |
|---|---|---|
| ⚖ Weight | 31.103 g ±0.3 g | More than ±0.3 g off |
| 📏 Diameter | 40.6 mm ±0.1 mm | Visibly off, or fails calipers |
| 📏 Thickness | ≈2.98 mm at the rim | Noticeably thick (hiding low density) |
| 🧲 Magnet | No attraction at all | Any pull = steel core |
| 🔔 Ring (c0d2) | 3.52–4.00 kHz | Any peak outside the bands below |
What fakes sound like — computed, metal by metal
A struck disc's ring is fixed by √(stiffness ÷ density). A genuine Silver American Eagle 1 oz rings its fundamental at 3.52–4.00 kHz (higher modes: 8.18–9.16 / 14.27–15.99 kHz). Here is where the same-size coin lands in the metals counterfeiters actually use — computed from published elastic constants, no guesswork:
| Struck in… | Fundamental | Weight at right size | What you'd hear |
|---|---|---|---|
| Genuine silver | 3.52–4.00 kHz | 31.103 g | clear, sustained ring |
| copper-nickel (struck fake) | ≈5700 Hz | ≈26.5 g | the most common struck-fake alloy — rings far higher than silver |
| silver-plated copper | ≈5050 Hz | ≈26.6 g | rings higher, decays faster, and comes in underweight |
| silver-plated zinc | ≈5450 Hz | ≈21.2 g | tinny, higher ring and badly underweight |
| steel core | ≈7050 Hz | ≈23.3 g | far higher ring — and the magnet test catches it before you even tap |
| silver-plated lead | ≈1650 Hz | ≈33.6 g | a dull, dead thud that dies instantly |
Plated and base-metal fakes also decay faster — solid precious metal has very low internal damping, so a genuine coin ring lasts; fakes die out. Coin Pinger measures both. Full resonance reference →
Known Silver American Eagle 1 oz fakes — what's actually out there
The dominant fake is a struck, silver-plated copper-alloy coin from China — NGC's XRF work on seized examples found bodies of roughly two-thirds copper with zinc and nickel and under 1% silver. Those alloys are lighter than silver, so fakes run underweight and undersized (one NGC-documented example: 30.6 g and 39.9 mm) or come out visibly thick; tells include mushy lettering, wrong date-digit fonts, and miscounted edge reeds. A scale, calipers, and the ring test catch nearly all of them — copper-nickel rings far higher and dies out faster than silver. JM Bullion's guide collects the visual tells.
Silver American Eagle 1 oz authenticity — frequently asked
How can I tell if my Silver American Eagle 1 oz is fake?
Run four checks: weight (genuine: 31.103 g ±0.3 g), diameter (40.6 mm ±0.1 mm), the magnet test (genuine silver is not magnetic), and the ring test — a genuine Silver American Eagle 1 oz's fundamental rings at 3.52–4.00 kHz, and every common fake metal rings measurably elsewhere. Passing all four is strong evidence of authenticity; failing any one is a red flag.
Does a fake Silver American Eagle 1 oz stick to a magnet?
Only steel-core fakes do — genuine silver is not magnetic, so any magnetic pull means fake. But most fakes (copper-nickel, plated copper) are also non-magnetic, so passing the magnet test proves little on its own. Combine it with weight and the ring.
How much does a fake Silver American Eagle 1 oz weigh?
A right-size fake in copper-nickel weighs about 26.5 g and in plated zinc about 21.2 g — versus 31.103 g genuine. Counterfeiters must choose: right weight with wrong size, or right size with wrong weight. Calipers plus a scale corner them; the ring test catches what both miss.
Can a counterfeit Silver American Eagle 1 oz pass the ping test?
A wrong-metal fake cannot — the ring is set by √(stiffness ÷ density), and no common fake metal matches silver's. The hardest case is a genuine-alloy counterfeit struck to correct specs; those are rare and expensive to make, and against them the ping test is one strong signal among several — combine it with weight, dimensions, and a trusted seller.