An interesting paradigm: How can a woman have soft bones and kidney stones at the same time? The bones are the biggest depository for calcium in the body. Women with osteoporosis can lose calcium from their bones and have it be deposited in her kidneys. From there it is flushed out as hard, jagged crystals that are excruciatingly painful to pass. Bones are actually made from 17 essential nutrients including magnesium which is the most important mineral along with calcium.