Black streak

Black streak

Many minerals have a black or dark grey streak. Graphite is a black mineral with a black streak. You probably see it every day - it is used to make the 'lead' in your pencil.

Other minerals, like galena and pyrolusite are also black or grey with black streaks. More surprisingly, the metallic yellow mineral chalcopyrite, often known as fools' gold, also has a black streak. Remember, a mineral's colour is not always the same as its streak.

Graphite, chalcopyrite and galena are minerals with a black streak.