It is never to forget but whatever type you buy among the above three. There are some very important points to take care of:
Jewelry shop may guarantee you for 24k or 22k.You need to look for hallmarking provided and authenticated by bureau of standards. Hallmark guarantees purity and fineness.
If you are going to break your traditional design for new one then don't do it if earlier you haven't got a purity certificate. You may never be able to compare it with recent rate given to you by jeweler.
Always retain the invoice and certificate( especially in case of gold with diamond or precious stones designs)
Ask for the actual gold weight apart from stones weight when you buy combination jewelry in gold.