7 On Your Side's buyers guide to diamond shopping for Valentine's Day

SAN FRANCISCO (KGO) -- When most people shop for diamonds they're shopping for the four C's: cut, color, clarity, and carat.

The Bay Area Consumers checkbook staff went undercover shopping for diamonds. They were looking at prices, quality, and very specific stones.

"Our undercover shoppers shopped around for two different types of diamonds at many stores and chains. We found huge prices differences. We are talking about one single stone costing from $10,000 to $17,000 or $18,000," said Kevin Brasler, from Bay Area Consumers Checkbook.

Adi Simayof, runs Simayof Diamond Cutters just off of San Francisco's Union Square, his store faired very well among those secret shoppers.

Simayof's prices beat most of the competition. "Most people are last minute shoppers they come on the last two or three days," said Simayof.

He says shoppers know what they are looking for and says focusing in on cut is a good idea.

"In the past, they were looking for size. Right now they are looking more for quality. So they are looking into the color, the clarity, and the cut. So the cut is the most important component in a diamond for them," said Simayof.

"You want to stick with diamonds that have excellent cuts that are certified and worry a lot less about color grade and or clarity or things like that because you can't see them with your naked eye, but they are going to cost you thousands of dollars," said Brasler.

Bottom line, very few jewelers will ever be inspecting your diamonds, so focus on what you can see.

Click here for more on the Consumer Checkbook undercover shopper report.