Brown, the most common natural-colored diamonds, have an uncommon appeal

With flashes of gold and pink, copper and peach, champagne diamonds captivate and enthrall to earn their fare share of the diamond market, and attention on the celebrity red carpet.

Imagine diamonds the color of champagne bubbles, sparkling as they rise up in a crystal glass; or the shade of warm cognac, catching the light at every angle. Or even the sheen of honey and caramel, butterscotch and chocolate, silkily diaphanous as they glow.

The shades and hues of brown diamonds, usually grouped under the category of champagne diamonds, can be light and pinkish-bubbly as the elite, effervescent wine; or dark, rich and spicy as cinnamon, nutmeg and cloves; but whether espresso-deep or café au lait-soft, their sparkle, fire and flash is as captivatingly warm as the whitest white diamond is cold.

No wonder white diamonds are called "ice."

But brown diamonds are very "hot." And getting hotter.

Although they are the most common natural-colored diamond, production in the world's largest diamond-producing mine, the Argyle Mine in Australia, has been down in recent years, and geologists and miners there have not discovered any new deposits.

And demand for champagne diamonds has increased. In recent years, $5 billion worth of champagne and cognac diamond jewelry has sold annually around the world, meaning these jewels are the most accessible natural-colored diamonds for consumers. As more and more celebrities have been spotted sporting all shades of brown diamonds on the red carpet, the popularity of these natural beauties has been taking off.Found in Australia, Africa, and Russia, the largest champagne diamond producer is the Argyle Diamond Mine, located in a remote corner of northwest Australia. The mine began producing in 1979 and along with champagne and cognac diamonds, also produces white and all varieties of fancy colored diamonds-yellow, blue, orange, green, red, purple and pink. Brown and yellow are the most common naturally-colored diamonds; red, blue and green are extremely rare, and pink is the rarest. Some brown and yellow diamonds can be irradiated and heated to produce the blue, red, and green shades, but these artificially-created colors are not as valued as the natural ones created by Mother Earth.