Woman's Best Friend

(CBS)  With Valentine's Day fast approaching, many men will be romancing the woman of their lives. And a few will even be popping the big question — meaning they'll need to find the perfect diamond engagement ring.

Carol Brodie Gelles, former spokeswoman for the Diamond Information Center and the current global director of communication for Harry Winston, visits The Early Show Tuesday to help men find that perfect stone for their love ones — leaving no stone unturned.

When planning to surprise a woman with a diamond engagement ring, 70 percent of men shop alone, according to the book, "How to Buy a Diamond."

With that in mind, Gelles says there are various-shaped engagement rings for them to choose from. The ring can come in oval, emerald, round, pear, marquis, cushion, radiant and heart shapes. She says they are all classic shapes, but the most sought-after rings are emerald and cushion.

Gelles says the first step to buying a diamond ring is to find an established and trusted source. Diamonds may look big and shiny under a store's bright lights, but they may be dull and flat in daylight. So, she suggests men get someone trustworthy behind the display cases to sell the ring that will hopefully last a lifetime.

Gelles says there are four "Cs" for men to look for when buying a diamond — color, cut, clarity and carat.

If the men think their brides-to-be are willing to receive a non-traditional ring, Gelles says colored rings are popular buys. Jennifer Lopez was glowing when she received a pink engagement ring from her fiancé Ben Affleck. The rings can also come in blue and yellow.

Besides the main stone, Gelles says a lot of people like to get diamonds on both sides of the stone, such as trillions or baguettes.

It's also important to know whether the person you'll be proposing to prefers white gold, yellow gold or platinum. Platinum is durable and more designs can be made with it, but nicks and dings are sometimes incurred as the ring is used.