Thank you for the responses. Calcium supplements are not that cheap for me and I can use a 50 pound bag of dolomitic limestone for a lifetime for a small sum. I can’t remember how much my garden ferilizer bag cost exactly but I take a pinch of pebbles every day or 2. I worry about impurities but I have not been grinding them up so I may not have been absorbing them anyway. I eat kefir each day or 2 but I wanted a source of magnesium because of constipation. Can epson salt be consumed safely? Thank you…