According to the Martha Stewart website, blue cheese is a general category of cheese that features blue or blue-green veins and spots created through an aging process with the mold Penicillium, while Gorgonzola is a specific variety within the spectrum of blue cheeses. Roquefort and Stilton are other popular examples found in the blue cheese family.
The unrefrigerated shelf life of cheese depends on its moisture content. Harder cheeses, such as Parmesan or Romano, have less moisture than soft cheeses like brie or ricotta. Soft, moist cheeses should not be left out for more than two hours. Hard grating cheeses can last longer.