Black Diamonds?!?

When Sarah Taylor, a 27-year-old law graduate from London, received an engagement ring, she was more than a little shocked, and not only because her boyfriend proposed on a railway platform in northern Scotland on a rainy Monday morning in March.

"It was black -- a band of tiny black diamonds, set in black gold," Ms. Taylor said. "When I finally managed to compose myself and look at the ring, it was exquisite."

Her 30-year-old fiancé, Paul Williams, a teacher, wanted to buy something different, so he opted for a black diamond. "Why go for bog-standard solitaire?" he said. "I wanted something out of the ordinary."

Mr. Williams turned out to be remarkably in touch. Tired of the garish bling that has come to epitomize Champagne-popping yacht hoppers, many shoppers are seeking out more original types of diamonds, with rough cuts or alternative hues -- and black diamonds have become a particularly popular choice. Apart from their own distinctive qualities, alternative diamonds are also a better credit-crunch choice: Both rough diamonds and treated, colored diamonds are cheaper than their polished counterparts.

Ms. Lampson said she likes using black diamonds because they reflect the light in a special way, flashing in a bright white. "If you see someone wearing a black diamond necklace, it catches your eye from the other side of the room," she said. "Unlike a white diamond, there are no rainbows, no internal reflection. They possess this very special opaqueness."

Hollywood also has given black diamonds a boost. Sarah Jessica Parker donned a black diamond strand necklace by American jeweler Itay Malkin in the "Sex and the City" movie, and Adrian Grenier sported a similar one in this season's finale of the TV show "Entourage." At the Baselworld jewelery fair in March -- a barometer of what's going to be hot in the coming year -- the pairing of black and white diamonds was one of the strongest trends. According to its organizers, the show featured a lot of "unpretentious jewelery" -- pieces that didn't draw attention to the wearer and could be worn every day, such as those with dark or rough stones.

Cult Mayfair-based jeweler Stephen Webster, whose neo-gothic crab rings, poison-ivy necklaces and knuckle dusters are worn by gothic-inclined celebrities, fashionistas and socialites, sees the shift in trend as part of a cultural zeitgeist. "Black diamonds are about dark glamour, which is perfect for today," Mr. Webster says. "There is a huge craze for the romantic, grown-up goth, symbolized by interest in [vampire TV] programs like 'True Blood.' I think this look has become quite seductive." Mr. Websters says that one of his clients -- a Russian art collector -- has commissioned him to make a £20,000 vampire ring that will include black diamonds. Mr. Webster added that black diamonds have captured another, previously untapped audience: "Earlier this year I made a bespoke black diamond tie-bar for Mickey Rourke, and Russell Brand is a real fan of our black-diamond pieces. Men are going mad for them -- it's the acceptable non-bling way to wear jewelery."

Black diamonds have a storied history. In medieval Italy, they were known as the "stones of reconciliation." A wave of a black diamond in the face of an unhappy spouse would, according to legend, clear things up. The Duke of Wellington admired them for their opaque beauty and reportedly owned a black diamond weighing 12.25 carats. One of the largest black diamonds in the world today -- the Spirit of de Grisogono -- comes in at a whopping 312 carats.

These show-stoppers are genuine black diamonds, which acquire their gloomy hue naturally because they have high concentrations of dark crystals, such as sulphides. Manufacturers also can treat diamonds to make them black. Modern processes have allowed them to enhance and change the color of poor-quality, muddy diamonds -- which would never be sold in their natural state -- in a laboratory, using radiation or heating. Both natural and treated black diamonds are much cheaper than your run-of-the-mill diamond. Whereas a one-carat white diamond can range from £3,000 to £8,000, a natural black diamond costs £250-£450 a carat, and treated black diamonds start at only £80-£120 a carat. Diamonds treated to become colors other than black cost from £500 to £2,000 a carat. (The real thing will cost you a small fortune -- "fancy color" natural diamonds, such as red, blue and yellow, are the most expensive in the world).

Rough diamonds are also becoming stylish. In keeping with more austere times, these natural stones are admired for their raw, organic quality. Worn by royals hundreds of year ago, before polishing techniques were mastered, they are enjoying a revival as people look to adorn themselves with less ostentatious, subtler rocks.

London jeweler Leonardo Pieroni has been using rough diamonds for more than 20 years. His beautiful, simple designs -- a gold band with a single stone is one of his signature styles -- are a way to own diamonds without breaking the bank. A four-carat rough diamond gold ring, for example, fetches £3,200 -- much cheaper than a polished rock of the same size, which would go for £10,500 to £250,000, depending on its quality.

Recently, however, rough diamonds have started to go luxe too. De Beers's Talisman collection, which is based on rough diamonds and features beautiful, rustic-style medallions, pendants and rings, is definitely not a budget option: A pair of yellow gold earrings containing 7.41 carats of rough and polished stones costs £16,500.

Another leader in rough-luxe diamond jewelery is American company Diamond in the Rough. Started four years ago by New York-based Anjanette Clisura and Daniel Eskapa, who felt there was something missing in the market, the company now sells its jewelry around the world. "I think that rough is so appealing because you get to see the stone exactly how nature has formed it," said Ms. Clisura, who became interested in rough gems over 10 years ago, when she was working for diamond miner Leviev. "So many years of heat, pressure and natural gasses have turned carbon into this amazing stone with all its natural crystal shapes. It has a perfect raw beauty."

Diamond in the Rough sells its jewelry at the Moussaieff stores in London and Geneva, with prices starting at £6,000 for a ring with a sizable rough diamond. Many pieces include smaller, polished diamonds as well. "There is a craze for everything that is natural these days, and these are something different, a conversation piece," said Alisa Moussaieff, Moussaieff's managing director and owner.

What's next for jewelery? Baselworld featured an array of purple-hued jewelery made from stones like agate and amethyst. In the U.K., Mayfair jeweler Mr. Webster says people are already searching for something edgier. "I've had huge demand for gray diamonds recently," he said. "They're definitely going to be the new black."

—Jemima Sissons is a writer based in London.