Blended or On The Rocks?
The International Bartenders Association (IBA) officially recognizes the margarita as a drink to be served "on the rocks" with salt rimmed around the glass. Despite these specifications, margaritas are frequently served blended and often without salt. The IBA does not make a specific tequila designation, though silver tequilas are usually preferable to gold.
Origin and Tradition
It is unclear exactly who invented the margarita and when, but most claims or origin place it in the 1930s or 40s in Mexico. Bartenders claiming to have invented the drink lived throughout the country, from Tijuana to Juarez to Acapulco. The drink had achieved further recognition around the world by the 1950s. It was the "drink of the month" from Esquire magazine in December 1953.