Up for your purchasing pleasure are these stunning sterling silver and turquoise (I think it may be turquoise, maybe howlite? ) clip on earrings from Taxco, Mexico oft called the silver capital of the world for the beauty of the silver that comes from there, and these earrings  set with a stunning turquoise stone shows the truth of those words. It is stamped TO-15 , Mexico and 925. Mexico adopted this hallmark style in the 1970s, where the first letter stands for the city in which the artist lived, the second the first letter of the craftmans last name. The number represents the order of registry. Unfortunately, Mexico did not keep records here so its hard to know who the artist is who created this piece. T stands for Taxco. 15  is a  low number given the people who have registered as silversmiths since the 1970s whose last name begins with "O", so this piece may be on the older side or by an older artisan. More information on Mexican hallmarks is at the wonderful site 925-1000 dot com.