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Gold coin guide
Mexican 50 Pesos Centenario — ping test & specs
The Centenario is the giant of classic gold: 41.67 g (1.2057 oz fine) of .900 gold at 37 mm. Its mass and breadth give it the deepest ring of the gold classics — and make it a prime counterfeiting target.
Opens the free tester with this coin preselected — audio never leaves your device.
Official specifications
| Weight | 41.6666 g |
| Diameter | 37 mm |
| Composition | .900 gold (90%) |
Source: Casa de Moneda de México (Banco de México). Coin Pinger checks measured weight and diameter against these values.
Expected resonance range
Good confidence*| Mode | Expected ring | Recommended variance |
|---|---|---|
| c0d2 | 3.09–3.90 kHz | ±11.5% |
| c0d3 | 7.17–8.96 kHz | ±11.1% |
| c0d4 | 12.49–15.61 kHz | ±11.1% |
A genuine Mexican 50 Pesos Centenario rings within these ranges at its c0d2/c0d3/c0d4 vibration modes, fixed by its size and metal. The recommended variance is how far a genuine specimen's ring can sit from each center — built up in quadrature from real manufacturing tolerance and temperature (under 1%), phone-mic capture reproducibility (≈4%), an extra allowance on the fundamental for minting-asymmetry splitting, and a per-metal model-uncertainty term (largest for .9999 gold, whose modulus is least certain). This coin's band is widened further because circulated 90%-silver classics lose mass and edge crispness with wear, spreading their ring. The higher modes also carry a small thick-plate centre correction, since a real coin is not infinitely thin. The good-confidence tag reflects how well-established this metal's constants are: Computed from 22k-gold alloy constants, which are slightly less certain than silver; the band is set accordingly. These are guidance bands, not exact values — see the methodology for the exact formula, or calibrate your own coin in the app for a specimen-exact reference and tighten each peak per coin.
Worried yours might be counterfeit? How to spot a fake Mexican 50 Pesos Centenario →
* These are computed guidance ranges. Certain your Mexican 50 Pesos Centenario is genuine but it won't match? Send us its ring — we'll dig in and improve the reference.
🎙 Submit sample pingsHow to ping test a Mexican 50 Pesos Centenario
- Hold — grip the coin by its center (a nodal point) in a coin ping-test holder so the rim rings freely; a fingertip at the center is a last resort.
- Tap — strike the edge with a striker near the microphone.
- Read the verdict — MATCH or NO MATCH against the peaks above, plus weight and size checks.
Mexican 50 Pesos Centenario — frequently asked
How much does a Mexican 50 Pesos Centenario weigh?
The official specification is 41.6666 g in .900 gold (90%) (source: Casa de Moneda de México (Banco de México)). Coin Pinger's weight check allows ±0.3 g by default. Circulated specimens lose a little mass to wear, so weigh toward the low side of that window.
What size is a Mexican 50 Pesos Centenario?
37 mm in diameter, per Casa de Moneda de México (Banco de México). Note the average disc thickness is less than the rim caliper reading — the raised rim and relief concentrate metal at the edge.
What frequency does a genuine Mexican 50 Pesos Centenario ring at?
Its fundamental (c0d2) vibration mode is computed to ring in the 3.09–3.90 kHz range, with higher modes near 7.17–8.96 kHz and 12.49–15.61 kHz. These are first-principles physics computations from the coin's published mass, diameter, and metal — not measurements of sample coins.
Why does my genuine Mexican 50 Pesos Centenario ring slightly off the listed frequencies?
Wear is the biggest factor for the Mexican 50 Pesos Centenario: circulated 90%-silver classics lose mass and edge crispness, which spreads the ring across specimens. On top of that, phone-mic capture moves a genuine peak a few percent tap-to-tap (strike point, how you hold it, the mic itself). That's why this reference band is wider than a modern bullion coin's.
Does ping testing damage a Mexican 50 Pesos Centenario?
No — the test needs only a light tap on the edge with a non-marring striker (a wooden pencil or plastic stylus works well), far gentler than normal handling. Hold the coin at its center so the rim can ring freely.