You have a sparkling ring on your finger. Congratulations.
In some cases, it is protected by homeowners or renters insurance. Check the details of your policy. Jewelry stores often sell insurance as well.
Usually I'd tell you that, like most extended warranties, it's a waste of money. NOT THIS TIME!
Gwen worked as a chef at a popular restaurant. She had a 1 1/4 carat heart shaped diamond in her engagement ring. One night, while making a vat of vegetable soup, the diamond fell out.
Fortunately, it was insured. She went to Zales and had the gem replaced. The moral of the story is that, if he's buying the ring brand new from a reputable dealer, spending a few extra bucks for insurance on the gemstones is probably a good idea.
Also see if the store has free jewelry cleaning and inspections. Had Gwen gotten her yearly inspection, perhaps the flawed prong would have been spotted and I wouldn't have that horror story to share.
There is also insurance for your wedding itself. I have never used it, nor known a bride who has, so I cannot speak with authority on the subject. http://www.reviews.com/wedding-insurance/ There's a link for those who wish to research the topic.