I am thinking about getting Yellow Sapphire, but I hear that it can create an imbalance of energies…
More Details about me:
I am Virgo Sun Sign, Cancer Rising, my Jupiter is at the 4th House.
Do I qualify for Yellow Sapphire? Let me know if you need more information about me.
I can’t find anything on google indicating it can cause unbalanced and in fact saw a few references to yellow sapphire being used to cause a balancing of energies. Supposedly it brings balance and equilibrium to your solar plexus energy center which in turn causes you to attract a sense of wealth, as well as shields you from negative energies and more.
Imop. Anyone qualifies for whatever stones they feel led to, for jewelry, altar adornments, talismans and the like, even it could cause issues for some people, the key is doing your research then getting a test stone and seeing how it works with you and your energy.
Check out this article then. There’s a segment that mentions “Side Effects”.
Right on, like I said you’ll probably have to do some deeper research and discern for yourself if that’s true or not and if studies back that up. 
I didn’t see anything like that when I searched for negative properties, but that was a surface search and just because it’s on the internet doesn’t mean it’s true, a deeper search or a stone to test will likely be the most useful for you