Blue cheese gets its name from the blue-green veins running through it, which develop because the cheese is deliberately ripened with a mould, usually Penicillium roqueforti. Roquefort, made in France using exactly this mould, is one of the oldest and most famous examples of this cheese category, and its name is often used to represent blue cheese in general. Cottage cheese is a fresh, unripened curd with no mould involved, and Camembert uses a white mould instead of a blue one, so blue cheese is commonly called Roquefort cheese.