Calcium and magnesium are essential to many bodily functions, particularly for bone density and strength. They also are important to maintaining muscle and nerve health. Calcium and magnesium work together. The recommended ratio of calcium to magnesium is 2:1. Although calcium is the central mineral in bone mineralization or calcification, the quality of the calcium crystals formed is dependent on magnesium. When magnesium levels are inadequate, the calcium crystals are weaker permitting fractures to occur. This occurs regardless of recommended daily consumption of calcium supplements. Muscle function requires both calcium and magnesium; calcium helps muscles contract and magnesium helps them relax.