@ Sagarchand,
All the three gems Blue Sapphire, Emerald and Chrysoberyl are for Shani/Saturn, Budha/Mercury, Ketu/Dragon’s Tail respecively. All three gel well with each other, support each other’s profile and can be worn together too. It will help in achieving the desired results well in time, with ease and speed. Go ahead and wear them.
I personally prefer wearing them in ring as they keep in touch with the skin all the time. But pendants may not be in contact with the skin all the time; being swayed everytime you move your neck or body.
The decision is yours, but keep in mind, results may take a long time with hurdles and delays, if worn as pendants.
Wishing you good luck, May God bless you, and above all…
Cheers