10 Shopping rules for buying a ring

1. EDUCATE YOURSELF
Before you hit the stores, you've got to learn to talk the talk. After all, how can you pick a stone if you don't know a carat from a karat? Know your 4Cs and how they affect the dazzle and value of your intended gem.

2. TUNE IN
Pay extra attention to your girlfriend's clothes and lifestyle. Platinum or gold? Diamond or ruby? Simple solitaire or fancy scrollwork? Try to gauge what she'll love -- and what fits her lifestyle. For example, sedentary types might love that Tiffany setting, but it's not a practical buy for superheroes.

3. SET A BUDGET
Determine your budget and stick to it. Keep in mind that you're better off buying a smaller, better-quality diamond than a big, dull rock.

4. DON'T RUSH
Decide when you want to propose, then allow ample time to shop around and plan a kick-butt proposal. Remember that once ordered, a ring can take up to six weeks to arrive, potentially longer if you're having it custom designed. (If you want to engrave something on the inside of the ring, be sure to request the inscription when you order.)

5. TRUST YOUR GUT
Only, we repeat, only shop at a jeweler who has been recommended or has a spotless reputation in your community. Safe bets are retailers associated with Jewelers of America or the American Gem Society. Otherwise, check with your local Chamber of Commerce or the Better Business Bureau and trust your intuition: What kind of vibe does the store have? Is the staff knowledgeable and patient? What are the return, repair, and replacement policies?

6. START SMART
Save time shopping by narrowing your search parameters first: For diamonds, first decide what shape, carat weight, and color grade you want. Next, compare the cut and clarity of different diamonds that fit the bill.

7. BUY DIAMONDS UNMOUNTED
Don't be dazzled by the pretty setting: Most jewelry ads are selling you on settings, not diamonds, even though the stone is a whopping 90% of a ring's cost! It's important to buy the stone loose, not mounted, so you can inspect the entire stone with a loupe (a small, handheld 10X magnifier that your jeweler can lend you) before you plunk down a load of cash. If the jeweler doesn't stock loose stones, move on.

8. ALL SET? NOT YET!
Now comes the really hard part: picking a setting. A few tips: If you go for a prong setting, platinum prongs are stronger than gold, which can also give the diamond a yellow cast. Make sure the ring's shank (the "ring" part of the ring) isn't too delicate, and ensure it's stamped with a quality mark (10K to 24K, PT, PLAT, PT950, IRIDPLAT) and the manufacturer's trademark. If the piece includes two metals, there should be a quality mark for each.

9. NEGOTIATE
Most retailers dramatically inflate prices. Never pay the sticker price unless you've shopped around and you know it's already a fair price.

10. GET IT IN WRITING
High-quality diamonds and diamonds one carat and larger should be accompanied by a diamond-grading report. If no report is included, make the sale contingent upon an independent appraiser's opinion. Once you get it appraised, get it insured.