@Geeta,
All these three gemstone mentioned by you above are variety of Corundum.
As per astrology, one should not wear Blue Sapphire along with Ruby and Yellow Sapphire as it is an anti-gemstone for Ruby and Yellow Sapphire. However, one can wear Ruby & Yellow Sapphire without any problem at the same time. For list of anti-gemstones click here.
Ruby should be worn on ring finger, yellow sapphire on index finger and blue sapphire on middle finger. But as said above, one should not wear all these three rings at the same time. Females should wear rings on the left hand while males should wear them on right hand.
It is unclear what you meant by “different time”? So, I will try to explain both aspects here.
- When you’re wearing gemstone ring for the first time you should wear it at auspicious time (shubh muhurat). However, if you wore the ring at any other time then you should take out the ring and then wear it again during auspicious time as mentioned here.
- If you wear only one ring and take it out after sometime to wear another ring then it is not advised. Either you wear only one ring or two rings.
I hope this helps.