I deleted my reply to this post, as at first i did not realise you were looking for the rubrics. I was going to mention that perhaps the child has a calcium deficiency which is causing the craving for chalk. I had 3 pregnancies in quick succession, and breastfeed also while pregnant. I ate chalk throughout the pregnancy with incredible cravings, and it was not until a tooth fell out that I realised the calcium connection. After increasing my calcium intake, the cravings subsided. I also had good results with cal carb later.