This is a 1957 Mexico 50 Pesos Gold Constitution Centennial Coin that was double struck in the Collar. It rotated between strikes and both designs from each strike are clearly visible. It is extremely rare for a modern Mexican gold coin of this size and weight to be double struck and accidentally issued by the Mint. The Mexico 50 Peso Gold Constitution Centennial Coin was struck to commemorate the centennial celebration of the Mexican constitution. It was minted from 90% fine gold at the Casa de Moneda de Mexico in Mexico City and has an actual gold weight of 1.205 troy oz.
1957 Mexico 50 Pesos Constitution Gold Double Struck in Collar PCGS MS 66