Dietary minerals are the chemical elements that living things need to have be part of what they eat, other than the four elements carbon, hydrogen, nitrogen, and oxygen which are already very common in living things.
One of the best known examples is calcium, which humans and many other animals need to build strong bones and teeth, among other things. Red meat is rich in iron which is a well known mineral. It is important for us to have iron as it creates red blood cells. Other common minerals include iron, potassium, and phosphorus.