Coin Pinger
Acoustic bullion authentication — free, private, on-device
Authenticity guide
Is my Silver Britannia 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 Britannia 1 oz | Red flag |
|---|---|---|
| ⚖ Weight | 31.21 g ±0.3 g | More than ±0.3 g off |
| 📏 Diameter | 38.61 mm ±0.1 mm | Visibly off, or fails calipers |
| 📏 Thickness | ≈3 mm at the rim | Noticeably thick (hiding low density) |
| 🧲 Magnet | No attraction at all | Any pull = steel core |
| 🔔 Ring (c0d2) | 4.31–4.91 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 Britannia 1 oz rings its fundamental at 4.31–4.91 kHz (higher modes: 10.00–11.21 / 17.37–19.47 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 | 4.31–4.91 kHz | 31.21 g | clear, sustained ring |
| copper-nickel (struck fake) | ≈7000 Hz | ≈26.6 g | the most common struck-fake alloy — rings far higher than silver |
| silver-plated copper | ≈6200 Hz | ≈26.7 g | rings higher, decays faster, and comes in underweight |
| silver-plated zinc | ≈6650 Hz | ≈21.2 g | tinny, higher ring and badly underweight |
| steel core | ≈8650 Hz | ≈23.4 g | far higher ring — and the magnet test catches it before you even tap |
| silver-plated lead | ≈2050 Hz | ≈33.7 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 Britannia 1 oz fakes — what's actually out there
Counterfeit Britannias documented on marketplaces are plated base metal — underweight or over-thick, with blurred detail, uneven reeding, and in some reported fakes odd parallel machining lines across the fields. Since 2021 the Royal Mint has struck what it calls "the most visually secure bullion coin": tilt a genuine coin and a latent image flips between a padlock and a trident, surface waves appear to move behind Britannia, and laser micro-text reads DECUS ET TUTAMEN. The tilt check is the quickest screen; the scale, calipers, and ring catch the plated tier.
Silver Britannia 1 oz authenticity — frequently asked
How can I tell if my Silver Britannia 1 oz is fake?
Run four checks: weight (genuine: 31.21 g ±0.3 g), diameter (38.61 mm ±0.1 mm), the magnet test (genuine silver is not magnetic), and the ring test — a genuine Silver Britannia 1 oz's fundamental rings at 4.31–4.91 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 Britannia 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 Britannia 1 oz weigh?
A right-size fake in copper-nickel weighs about 26.6 g and in plated zinc about 21.2 g — versus 31.21 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 Britannia 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.