@ Lalit,
It is not clear why you are asking this question now. Placement wise Saturn is in the 9th house which is the badhaka sthana as well. It is retrograde. It is aspected by the 6th lord Venus, 8th lord Jupiter and the 12th lord Mars. It occupies the 12th amsa (from natal lagna) in the navamsa (its debilitation house).
Dasa of Saturn started in 2018 for you. Sade sati is in its final 2 years. Under such conditions, what prompted you to check for suitability of blue sapphire is intriguing. You could state your problem more clearly so that a considered response can be given.