She is noted for inventing a technique to make the local pottery type, barro negro, black and shiny after firing.
The origins of barro negro pottery extend over centuries, with examples of it found at a number of Mexican archeological sites, fashioned mostly into jars and other utilitarian items.
The barro negro pottery of Doña Rosa’s hometown of San Bartolo has been traditionally used to make large “cántaros”, tall vessels used for storing and transporting liquids, including mezcal.
[2][3] This innovation makes the pieces more breakable, but it has made the pottery far more popular with Mexican folk art collectors, which included Nelson Rockefeller, who promoted it in the United States.
[4] The popularity stems from the look, rather than durability, so many pieces such as containers, whistles, flutes, bells, masks, lamps and animal figures are produced now for decorative purposes rather than utilitarian.