Calcification is the biological process where salts of calcium build up on soft tissue within the body, eventually causing them to harden. Although it is often a benign process (for example, the pineal gland calcifies in most adults), it can indicate a serious underlying condition such as Vitamin K deficiency or a combination of high levels of Vitamin D with high levels of dietary calcium.
Some common calcifications are the buildup of tartar on the teeth and gums, calluses, bone spurs, kidney stones, and gallstones.