Diamonds are a girl's best friend, but for some girls, white diamonds (search) just aren't good enough anymore.

The rich and famous have fallen in love with colored diamonds, which are rarer and exponentially more expensive than their white counterparts. And the trend is inspiring regular consumers who follow the latest style icons.

"They're absolutely more popular," said Carolyn Brodie Gelles, global director of communications for elite jeweler Harry Winston. "People with a lot of money found out they could have something that no one else would have."

In part, experts attribute the growing buzz about the gems to the woman who has influenced everything from derrieres to "bling bling": Jennifer Lopez (search), whose giant, pink Harry Winston engagement ring from Ben Affleck caused fashionistas to drool.

"J-Lo was a big force behind the trend," Brodie Gelles said. "Pink is our color and Jen is our girl."

E!'s fashion director Elycia Rubin predicted Lopez's ring choice will influence other Hollywood stars, and in turn inspire women everywhere.

"You'll be seeing a lot more colored diamonds on the red carpet. The amount of press that Jen's ring got set it off even more," she said. "It will trickle down to the consumer in the form of other colored gems."

Brodie Gelles said the individuality of colored diamonds is another driving force behind the trend.

"The supply is very limited and each one is different," she said.

Colored diamonds come in every shade of the rainbow and are extremely rare. Some, like the yellow ones, are colored by the naturally occurring addition of elements such as nitrogen, whereas pink diamonds simply reflect light differently than white diamonds.

Fueling the fad, the Smithsonian Museum of Natural History is currently displaying The Splendor of Diamonds. The exhibit showcases seven of the most famous colored diamonds, including Harry Winston's orange Pumpkin diamond and De Beers' Allnatt yellow diamond.

"People are finding out about them and seeing that they're pretty unique," said Smithsonian gem collection manager Russell Feather. "Most people in the diamond industry never even get to see things like this."

Feather said the exhibit, which runs through Sept. 15, is one of the most popular temporary shows they've ever done.

"People have been hearing about them. Now this is a chance to see them," he said, citing the purple diamond that embattled NBA star Kobe Bryant (search) reportedly gave his wife earlier this month to make up for his admitted adultery.

Extravagant as they may be, colored diamonds aren't just for millionaire sports stars and pop-music divas.

Kristen Schultz, a 27-year-old journalist, fell in love with a yellow diamond engagement ring she saw last year in Chicago.

"I like the color yellow and I always try to combine the non-traditional with the traditional," she said. "I don't want something that everybody has, and I’ve seen every incarnation of white diamonds."

Considering the price of large colored diamonds -- they start at about $50,000 -- Schultz is planning to get either a canary yellow eternity band made of less expensive small yellow diamonds or a white diamond with a yellow gem on each side.

Although using yellow diamonds will make for a more expensive ring, Schultz thinks it’s worth the price. "These are more rare, so they should cost more," she said. 

However, while Schultz wants something unique, she doesn't think an engagement ring should break the bank. "I don’t think it should interfere with plans for an apartment or house or vacation, or that you should take out loans or go into debt over your ring."

Brodie Gelles said Winston makes white diamond crosses with pink center stones for $3,400. And another more affordable option is to substitute other colored gems for diamonds.

"After pink diamonds people will go to pink sapphires, then pink tourmaline. We've even had pink morganite," said Brodie Gelles.

Trend aside, newly-engaged law student Alexandra Rigney, 24, had her heart set on a traditional white diamond engagement ring.

"I just wanted something simple," she said. "Huge colored rings are a little gaudy. They remind me of those huge colored plastic rings.”

Brodie Gelles thinks more and more upper crusters will begin to seek pink, blue and other colored stones. But as for Rigney, she's tickled pink by her new white diamond.

"It could have been orange – anything from Jim would have made me happy," she said of her fiancé. "And frankly, I don't know if I’ve ever considered doing anything J-Lo has done."