Coin Pinger
Acoustic bullion authentication — free, private, on-device
Authenticity guide
Is my Mercury Dime (1916–1945) 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 Mercury Dime (1916–1945) | Red flag |
|---|---|---|
| ⚖ Weight | 2.5 g ±0.3 g (wear trims a little) | More than ±0.3 g off |
| 📏 Diameter | 17.91 mm ±0.1 mm | Visibly off, or fails calipers |
| 🧲 Magnet | No attraction at all | Any pull = steel core |
| 🔔 Ring (c0d2) | 7.39–9.23 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 Mercury Dime (1916–1945) rings its fundamental at 7.39–9.23 kHz (higher modes: 17.14–21.24 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 | 7.39–9.23 kHz | 2.5 g | clear, sustained ring |
| copper-nickel (struck fake) | ≈12300 Hz | ≈2.2 g | the most common struck-fake alloy — rings far higher than silver |
| silver-plated copper | ≈10850 Hz | ≈2.2 g | rings higher, decays faster, and comes in underweight |
| silver-plated zinc | ≈11700 Hz | ≈1.7 g | tinny, higher ring and badly underweight |
| steel core | ≈15150 Hz | ≈1.9 g | far higher ring — and the magnet test catches it before you even tap |
| silver-plated lead | ≈3550 Hz | ≈2.7 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 Mercury Dime (1916–1945) fakes — what's actually out there
Documented faking targets the numismatic key date, not bullion: the 1916-D is NGC's second-most-counterfeited US coin, and most fakes are genuine silver dimes with a soldered or retooled mintmark — they pass every metal test, including this one; only mintmark diagnostics catch them. Modern cast fakes of common junk-silver dates do exist (mold seams, chunky relief, wrong weight, dead ring), though faking sub-dollar silver remains marginal. Honest summary: the ring verifies your dime is silver — it cannot verify a 1916-D premium.
Mercury Dime (1916–1945) authenticity — frequently asked
How can I tell if my Mercury Dime (1916–1945) is fake?
Run four checks: weight (genuine: 2.5 g ±0.3 g, a bit less with heavy wear), diameter (17.91 mm ±0.1 mm), the magnet test (genuine silver is not magnetic), and the ring test — a genuine Mercury Dime (1916–1945)'s fundamental rings at 7.39–9.23 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 Mercury Dime (1916–1945) 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 Mercury Dime (1916–1945) weigh?
A right-size fake in copper-nickel weighs about 2.2 g and in plated zinc about 1.7 g — versus 2.5 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 Mercury Dime (1916–1945) 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.