Exactly what I was thinking. Bet they're iron, about 70% less dense and a good supplement for your blood cells. https://www.wolframalpha.com/input?i=densiy+of+i

Exactly what I was thinking. Bet they're iron, about 70% less dense and a good supplement for your blood cells. https://www.wolframalpha.com/input?i=densiy+of+iron%2Fdensity+of+lead https://www.wolframalpha.com/input?i=densiy+of+iron%2Fdensit...