Pingcoin

People buying or collecting gold and silver coins, at coin shows, estate sales, or from private sellers, have no easy way to verify authenticity on the spot. Professional verification tools like Sigma verifiers cost $1,500+ and XRF scanners cost $30,000, putting them out of reach for individual collectors and casual buyers. Without such tools, buyers are left relying on weight, dimensions, or visual inspection alone, or simply buying blind. The cost of getting it wrong is significant: the site states a single fake gold coin can cost a buyer $4,000+.

Pingcoin is a smartphone app for iPhone and Android that digitizes the traditional 'ping test,' where a coin is tapped and its ring is used to judge authenticity. The app captures a coin's acoustic signature when tapped and compares it in milliseconds against verified reference frequencies for 43 supported coin types (27 silver, 16 gold), covering popular bullion like Eagles, Maple Leafs, Krugerrands, and Philharmonics. It returns an 'Authentic' or 'Not Recognized' verdict within seconds, works fully offline with no audio leaving the device, requires no special equipment, and causes no damage to the coin. The company says it backs the method with Finite Element Method (FEM) vibrational modeling and positions it as a complement to, not replacement for, weight, dimension, and visual checks. It also offers a 'False Positive Guarantee,' committing to buy a qualifying coin specimen at spot value if it passes weight, dimension, and ping checks but is later shown to be fake, plus a separate $50 bounty for reproducible false passes on non-coin objects.