The Mexican Revolution
The coins of the Mexican Revolution fluctuate in quality, from the well-minted coins of the federal government issues that circulated when the Revolution began to the crudest castings created by pouring molten metal into a mold of sand. Copper and brass were generally used for the blanks, but examples of silver, lead, cardboard, and maybe red clay are also known. The design used the traditional themes of Mexican coinage.
José Manuel Sobrino points out that, given the rudimentary resources, it is not surprising that the pieces produced were, for the most part, of crude manufacture, except perhaps the provisional coins of Oaxaca and the issues of Villa.
Most revolutionary coins have a GB number following the listing in Hugh S. Guthrie and Merrill Bothamley’s Mexican Revolutionary Coinage, 1913-1917, but other classifications include KM- (from Krause-Mishler’s Standard Catalogue of World Coins, OAX- for Oaxaca coins (from C. “Woody” Woodworth and Joe Flores’ La Ventanaavailable in the USMexNA online library, and A-, from Carlos Abel Amaya Guerra’s Compendio de la Moneda de la Revolución Mexicana.