I had a habit of eating sand pot I don't what it's exactly called in english but in india we call it *matka* and cement from wall. My family doctor said I had calcium deficiency that's why then after sometimes I stopped and then again started when I was around 16 years old and stopped again now I started again I mean I crave it I really don't wanna eat it but can't resist. What to do? And is it harmful to me? Please help.