Please accept my condolences if your mom has passed.
I agree with having a reputable jeweler look at it. They might not want it, though, but at least you will have an opinion. Maybe take it to two places?
The jewelry from online shopping is often not very solid (hollow rope chains, for example), so the gold weight is probably lower than appearance indicates. Good luck!
Edited to say that, if they don't take up too much space, you might just want to pick the ones you like and keep these use as gifts for the ladies in your life. Have a lady friend help you pick. That way you can even include a little note that your Mom left it to you and that you thought they'd like it. Look up the birthstones for different months for added gifting power at birthday time. Do you have nieces, daughters, etc? I get gifts from relatives like this and I always enjoy that touch.