@ Abhishek,
In case of Yellow Sapphire, the gemstione should be facetted (transparent) type only. It should have good cut and it should not have any hairline crack inside the gemstone. And if there is any inclusion (it is not acceptable generally) then it has to be checked by an astrologer. And Saloni Pukhraj is good as it only comes from Srilanka.
Regarding muhurtham for wearing the gemstone, I see that there is not auspicious muhurtham (100% or atleast 75%) on nearby dates. Frankly speaking you are very lucky you got quite near by date. You have to wear the gemstone on 17-04-2014 that is April 17th, Thursday.
Timings: – 11.00 to 11.20 AM
I have considered your birth place as Dehradun, India.
And before wearing the gemstone, it has to be set in an gold ring. If not gold, you can use pancha dhatu ring. Please be carefull that Pukhraj (Yellow Sapphire) is not as solid as diamond, even little hard hit can create a hair line crack inside, which can be seen by a magnifier.
Before wearing, perform the procedure which I have given earlier to another user. You can view the link below:
http://www.gemstonebuzz.com/forum/astrology/598/how-to-clean-and-recharge-gemstone
The beeja mantra which you have to meditate is given below (also provided in link above):
OM GRAAM GREEM GROUM SHA GURUVE NAMAHA!!!
GOD BLESS!!!
Srinivasa Temkar