The engagement ring may be one of the biggest expenses of your wedding , and as with buying any big-ticket item, you need to do your homework. We tapped Jerry Ehrenwald, the president of the International Gemological Institute , for some quick guidelines on what couples need to do when they're buying an engagement ring.
- Learn about the four Cs. "Before purchasing a diamond, learn all about the four Cs  — the color of the diamond, the clarity of the diamond, the quality of the cut of the diamond, and the carat weight of the diamond."
- Check out reputable stores. "Shop at reputable jewelry sources. Make purchases from a jeweler who has been in business for a number of years. If you are not familiar with the jeweler or online site, check their reputation and rating with the Better Business Bureau before you buy."
- Buy a certified diamond. "Certified means that a diamond rating report has been issued by an independent, unbiased gemological institute. This way, the consumer has the opportunity to compare one diamond's quality to that of another, with regard to the value and quality of the diamond they're looking at."
- Grading report. "Purchase diamond jewelry accompanied by a grading report. The grading report provides an unbiased assessment of a jewel's four Cs. It informs you if a stone is synthetic — in other words, man-made or laboratory grown — or has undergone any treatments, which may dramatically affect the value. Be sure an accredited gemological institute, such as IGI, has graded the diamond jewelry to the one internationally accepted system for diamond grading."
- Understand the store's return policy. "Most reputable retailers have at least a 30-day, money-back guarantee, although there may be some cases where the jewelry is not returnable, such as if it has been custom-fabricated to the particular client or engraved with unique initials or things like that, which would not make it readily salable to other people."
- Use a credit card. Pay with a credit card for better protection. The Fair Credit Billing Act  protects credit card transactions. If you run into any problems, make sure you deal with it as soon as possible to qualify for the law's consumer protections.
- Remember the receipt. "Keep the receipt for your records, as it's a legal document that protects the consumer should anything happen to the diamond. It's vital when purchasing jewelry insurance or making a return."
These simple guidelines are a good starting point for your ring research, but there are other factors to keep in mind such as ring insurance and whether you want a conflict-free diamond. Do more extensive research before buying to prevent buyer's remorse.