You are what your Rashi is. Many times we face times which are unbearable and make us depressed and we need some divine help. For this reason only God made these Gem Stones which are no less than gift of God to people in distress. Hindu saints propagated the use of these stone for common man to ward off evils surrounding him.
According to Acahrya Devvrat, these stones can change destiny. If one is having problem of lack of money or in family then he must wear these stones. These rings are made free size so any one can wear it without any problem.