Why frequency alone isn't enough:
Zinc-core fakes often ring at a higher frequency than silver (zinc is stiffer relative to its density),
while lead-core fakes ring much lower. The critical tell is the sustain:
genuine silver rings for 1–3 seconds; base-metal fakes die in under 0.3 s.
This tool checks both.
Pencil Calibration
⚠ Not calibrated — tap two pencils together first for best results
Always use a pencil to strike the coin — it produces a clean, light tap with minimal added noise
To calibrate: click Calibrate Pencil, then tap two pencils together once near the mic
The tool captures the pencil’s own resonance and subtracts it from your coin test result
Calibration saves to your browser and persists across visits — clear and redo if you change pencils
Listen & Test
Listen — see the live frequency display. Test — strike your coin to get a verdict.
Listen: turns on the mic and shows the live frequency chart — no result produced
Test: arms capture; strike your coin and the tool analyses the ring to give a verdict
Hold the coin loosely between thumb and forefinger at its edge — never flat on a surface
Strike the rim firmly with a pencil — calibrate the pencil first (card above) for best results
Already listening? Click Test to arm the capture without restarting the mic
Frequency Chart
Predicted mode positions for selected coin
Waveform (captured ring)
Ring duration
Important: The ping test is a useful screening tool but is not definitive proof of authenticity.
Professional verification (specific gravity / Archimedes test, XRF analyser) is recommended for high-value purchases.
Coin dimensions in this database are best-available figures — always verify against your assay certificate.
The Eisenhower Bicentennial $1 silver edition is the 40% Ag collector proof/uncirculated (S mint mark);
the common circulation coin is clad copper-nickel with no silver and is included only as a reference.
Predicted frequencies use thin-disc free-edge plate vibration theory and are approximate.