When in 1999 Michel Einhorn launched www.cooldiamonds.com to sell diamond jewellery online, his family – most working in the diamond industry – said it would never work. Seven years on, the site has seen sales grow by 660 per cent, and receives up to 5m hits a month.

Jewellery appeals to the senses and emotions so it is not an obvious purchase to make in the cold, impersonal world of cyberspace. The argument goes that to experience fully the magic of precious stones, gold and platinum, they need to be touched and worn to enjoy the full, sparkling effect – something that just is not possible by looking at a computer screen.

Surprisingly, Cool Diamonds is not a one-off success story.

According to a global report, towards the end of last year, visits to jewellery and luxury goods websites grew faster than any other internet category. And visits are being translated into sales.

Jewellery e-tailers such as Blue Nile, Gerald Online (brainchild of the infamous Gerald Ratner) and Jewellery.tv are reporting strong growth – in some cases sales are doubling or even tripling month-on-month, while top-end brands such as Tiffany, Louis Vuitton, Links of London and Dunhill are taking their e-commerce capabilities more seriously than ever before.

“Now people are buying books and CDs online without a second thought, it makes sense they are more confident about spending money on luxury items such as jewellery – particularly time-poor, cash-rich consumers, who are looking for convenience,” says Catherine Macdonald-Keir, editor of Luxury Briefing magazine. At Cool Diamonds, Mr Einhorn agrees that growing consumer confidence in the internet has played a vital role in its growth, encouraging consumers to spend more money per purchase.

The average ticket price at Cool Diamonds has risen from £1,000 when the site first launched, to £3,100.

Hand-in-hand with growing trust in the internet goes an increased trust in the brands themselves.

High-quality websites using the latest technology alongside growing use of broadband provide crystal-clear images so consumers can see what they are buying. “When the consumer is spending a lot of money, they need to have a totally realistic view of the product and with digital technology, we can show customers every aspect of the diamond,” says Mr Einhorn.

“It can be seen in 3D and enlarged, and we use a high-magnification machine that shows every facet of the diamond. Yes, some consumers want to see and touch the pieces, but for those that don’t have time to go to the shops, this really helps them to get a feel.”

Price is another important factor.

With fewer overheads and a more streamlined supply chain (the middle-man is often cut out), prices on the web can be up to 40 per cent lower than on the high street.

“People are aware of this and use the internet to research the lowest possible price,” says Gerald Ratner of Gerald Online. “On the internet, you can easily compare diamond for diamond. Consumers know that they can get it cheaper and for many, this outweighs the disadvantage of not being able to see the piece in the flesh.”

Jewellery websites are also a mine of information and allow the uninformed to research everything they can about the product.

“It can be so intimidating – particularly for men – to walk into a jeweller and be confronted with an array of diamonds of all shapes, sizes and prices,” says Ms Macdonald-Keir. “On the internet you don’t have to show your ignorance – or the size of your wallet - to anyone. It empowers the customer to find out as much as they can before they go ahead and buy,” she says.

Jewellery e-tailers cater not only for nervous men about to propose or panicked husbands looking for a last-minute anniversary present. “Women are increasingly buying jewellery themselves to wear as fashion accessories – even at the high-end – primarily because they can now afford to pay for it, rather than wait for a man to buy for them,” says Ms Macdonald-Keir.

“This, with the fact that women have taken over from men as more prolific on-line shoppers, means it’s no wonder growth in online jewellery sales is on the up.”

Brands are beginning to take advantage of this trend and are designing websites that offer advice on styling and fashion.

Jewellery brand Links of London, whose website sales have grown annually by 40 per cent, is relaunching its website to be more editorially-led. “The web can be a bit cold and we want to enhance the visitor’s experience, taking it beyond just showing them the product,” says chairman John Ayton.

Designer jewellery website Manjoh.com, whose sales doubled over Christmas, does just that.

Offering a luxury online environment in a magazine-style format with detailed descriptions of the jewellery and features on the latest trends, buyer Rukhi Sohi says: “It really helps our customers, who wear jewellery as a fashion statement, and it helps sales too – when we ran a feature on long beaded necklaces, sales of those pieces shot up.”

Cool Diamonds has extended its collection to include jewellery by designers Bruce Oldfield, Jasper Conran and Vivienne Westwood.

“More women are buying jewellery for themselves for more than £1,000 – they can afford it, and they want designs with a difference,” says Mr Einhorn.

Mr Ayton agrees that women looking for more unusual designs, such as Links’ unique Annoushka Collection.

“We have limited offline distribution, so for people that have a long way to travel to our stores or live in areas without access to designer jewellers, buying online may be the only solution,” he says. Plus, he adds, there’s always the 30-day money back guarantee that every distance retailer has to agree to.

That the jewellery can be tried on in the comfort of the customer’s own home and sent straight back if they don’t like it, may well clinch the deal for many an online jewellery buyer.

But the fact that returns are rare – generally less than 5 per cent of sales – shows that once the customer can see and touch the piece in all its sparkling glory, it can be hard to let the magic go. And it provides a wonderful reminder that the very same reason the pessimistic pundits said selling jewellery online would never catch on might turn into the very reason it is becoming such a success.