OK, so you want a diamond. Are you going to a) Venture into a plush shop, be flattered by a smarmy assistant, and leave with your little baby nestling in an instantly recognizable box (which you can't wear). Or, b) Look on the internet and congratulate yourself on your savvy shopping skills? Well, it all depends on who you are and what you're after. You may be looking for something with a modicum of intrinsically valuable design. Or you might take the view that diamonds are already so beyond reason that you would rather keep the experience deliciously pure and do it the old-fashioned way. In either case, be my guest- sally forth on the Bond Street and treasure those Pretty Woman shopping memories for the rest of your life.

On the other hand, you may want a bog-standard diamond solitaire ring set in white gold and be looking for the biggest bang your buck can buy. In which case, short of waiting for your chosen ring type come up at auction, you can probably do no worse than spend your lunch hour on the internet. The rise of internet diamond sales has been the single biggest factor in the decline of the diamond market's profitability- for which, read cheaper diamonds for us. Canny shoppers have trawled the net and are using the plethora of pleasingly cheap sites to beat down regular retail prices. As Martin Rapport, author of the eponymous industry standard pricing guide says: "In the old days, people used to sell the diamond and give away the setting, so the profit would be in the diamond. Today, they give away the diamond and sell the mounting, because the profits in trading diamonds have cone down.

He feels that the internet is driving transparency and efficiency into the diamond markets. The internet provides instant information and comparisons. So why would you spend more at the shop for a diamond you could buy on the net? "Retailers do add value in presenting them to the customer and particularly in more complicated jewellery" says "but they are now going to have to justify their added value propositions". Which means it's up to you exactly how much that design or even just plain packaging its worth. Of course, there is always the issue of confidence. The big jewellery brands have built whiter-than-white reputations, while the www.random-diamond-site-you-found-at-3-in-the-morning.com may look fancy, but actually be run by a con artist out of his garage. The answer to this is to insist on an independent diamond grading report (which tells you exactly what you are buying, not how much its worth) from one of the big labs such as the GIA, AnchorCert or the Gemological Associations. "The grading reports attempt to create a level playing field" says Rappaport. He suggests taking the concept of diamond grading reports a step further and we are looking at the commoditization of diamonds. "You want to buy the diamond at the best price. It's my belief that diamonds will be traded on the internet, like stocks are traded on Nasdaq. If you can trade pork bellies, why can't you trade diamonds?" But in the meantime, back to the fabulous jewellery you were about to buy. Google throws up more diamond sites than Paris Hilton references, so here's what to look for. Only shop on sites that offer a money-back guarantee, and independent-grading report and which tell you specifically about the four Cs of the stone you are buying. In case you weren't paying attention last time I mentioned it, that's the colour, cut, clarity and carat weight of a diamond. That way you can make a fully informed, if not rational, decision."