Many years ago at a time of significant stress in my life I was quite touched one day when one of my children gave me a present of this worry stone. The theory was that if you rubbed your thumb in the little curved indentation it would help soothe your stress. I'm not sure if it achieved that but it showed me how my response to our difficulties was being perceived by the children and it helped me to "wise up" and try to deal with it more sensibly.