Pink and Red Diamonds
Before Argyle, most pink diamonds were a pastel shade worthy of passing interest, but not lasting passion. This all changed when the first Argyle Pink diamonds were released in 1985. Australia's Argyle mine in the north of WA produces almost all of the worlds' red and pink diamonds. Although it is the worlds largest diamond mine, most of its diamonds are champagne and cognac colour. Around 0.1% are pink.

Scientists still do not fully understand the cause of the pink colour. Usually colour is caused by impurities, but Argyle diamonds are very pure. They are found in a rock called Lamproite that appears to have had a particularly violent journey through the earths crust. (All other diamonds were transported to the earth's surface in a rock called Kimberlite). This unique host rock means it is unlikely another mine like Argyle will ever be found. So when Argyle drys up its sayonara pink diamonds!

- David Fardon from Argyle on the rarity of pinks

Argyle Tender
Argyle offers its finest 50 or so pink diamonds each year in a sealed bid tender. Some years the tender includes a red diamond. The event has become widely reported. The tender opens in Sydney before a week in Hong Kong, Tokyo, New York, London and finally Geneva where the bids are opened. This annual event has raised the profile of pink diamonds. Prices usually exceed US$100,000 per carat. Many of the worlds rich and famous are the eventual owners. It is said the Sultan of Brunei has a standing bid of US $1million for any red diamond bigger than 1ct. Apparently he is building a collection that will one day appear as a magnificent suite of jewellery. Some of the diamonds are still waiting to be unearthed in WA.

Champagne Diamonds
Champagne and Cognac diamonds are the best coloured diamond buys, at around one third the price of white diamonds. This good buying will not last forever.

Prices for colours C1 to C6 are all about the same. Lighter stones are popular because they sparkle a lot and cost less. More intense colours are also popular because the colours are so beautiful, so supply and demand are fairly balanced. You can simply choose the colour you like best without worrying about which is more valuable. However there are many different secondary colours and this is important. In general warmer colours are more attractive than grey-greenish browns. Intense golden and rusty colours are called fancy Cognac, or C7 and cost a little more. Naturally champagnes with a pinkish tinge are the most sought after and expensive.

Champagne diamonds (and most other coloured diamonds) are often more heavily included than white diamonds. At Precious Metals we relax our rigid clarity and cut policies with fancy coloured diamonds because the important thing is the way the colour "faces up".

What Causes Colour in Diamond?
Diamonds are very pure carbon that crystallised more than 100km beneath the earth's surface. Diamonds grow under immense heat and pressure (Even Superman could not have made them) and are transported to the surface within an hour or two in a volcano. In a way they are snap frozen because if the journey takes too long they revert back to graphite or carbonaceous gases.

Sometimes other atoms are trapped in a diamond as it grows or during its violent ride to the surface. The most common is Nitrogen; the tiniest amount causes blue light to be absorbed giving the diamond a yellowish colour.

Rarity
Intensely coloured diamonds are the rarest and most beautiful of nature's gem treasures. Rarity and desire are the two things that set the price of coloured diamonds. The rarest and most prized in order are red, pink, blue, green, gold and then yellow, milky white, champagne and black. Values can be 100 times more than that of a white diamond!

The highest price per-carat ever paid for a gem was $1,250,000 for a 6mm purplish-red badly flawed diamond of less than 1 carat (inclusions are common in natural red and pink diamonds).

What Causes Colour in Diamond?
Diamonds are very pure carbon that crystallised more than 100km beneath the earth's surface. Diamonds grow under immense heat and pressure (Even Superman could not have made them) and are transported to the surface within an hour or two in a volcano. In a way they are snap frozen because if the journey takes too long they revert back to graphite or carbonaceous gases.

Sometimes other atoms are trapped in a diamond as it grows or during its violent ride to the surface. The most common is Nitrogen; the tiniest amount causes blue light to be absorbed giving the diamond a yellowish colour.

Rarity
Intensely coloured diamonds are the rarest and most beautiful of nature's gem treasures. Rarity and desire are the two things that set the price of coloured diamonds. The rarest and most prized in order are red, pink, blue, green, gold and then yellow, milky white, champagne and black. Values can be 100 times more than that of a white diamond!

The highest price per-carat ever paid for a gem was $1,250,000 for a 6mm purplish-red badly flawed diamond of less than 1 carat (inclusions are common in natural red and pink diamonds).

Hope Diamond 45.53 Carats

Dresden Green 41 Carats

Other Colours

Blue Diamonds
Natural blue diamonds are a light greyish blue shade, a more "steely" colour than sapphire. The most famous blue diamond is the "Hope" diamond in Washington's Smithsonian Institute. This stone is steeped in legends. Its last owner was New York jeweller Harry Winston. He purchased it to donate to the Smithsonian and only owned it for one day. While his insurance company and armed couriers were discussing the cost and method of delivering the priceless gem to Washington, Harry strolled down to the post office and posted the diamond in a cigarette packet as ordinary mail!

Precious Metals have access to the dozen or so violet-grey blue diamonds found each year at Argyle.

Green Diamonds
Green diamonds have comes in contact with radioactive minerals such as uranium. Radiation stains the outside of the diamond, so the cutter must be careful not to cut away too much of the green "skin". Authenticating that the radiation occurred naturally requires laboratory analysis at a leading gemmological institute. Buyer beware!

Yellow and Orange Diamonds
To be called a Fancy colour means the diamond has more colour than Z on the GIA D-Z white diamond grading scale. Fancy yellow diamonds come in a range of hues from greenish yellow to amber. They start at similar prices to white diamonds and prices raise with increasing intensity. Connoisseurs in the trade use the term "canary" to describe intense yellow. Burnt orange Argyle champagne's are a less expensive alternative to very expensive pure gold or orange colours.

We have a nice collection of moderate to intense yellow, greenish yellow and gold coloured diamonds.

White-milky Diamonds
A little known and quite rare diamond is a white opalescent diamond. These are collector's oddities and we have a small selection at Precious Metals. They are a lot less expensive than colourless diamonds, and we think they were a real bargain. There have been articles written about them recently in Gems and Gemology, the GIA in America's prestigious journal. Who knows they may become the next fashion thing like black diamonds.

Black Diamonds
Pave' set* Black diamonds are the in thing in Europe at present. We think they make great men's jewellery for Aussie blokes, and we have understated rings and cuff links for the rough diamond in a woman's life. Most of the black diamond fashion jewellery is made with treated coloured diamonds. Blacks with a good surface luster are rare, but naturally we specialize in untreated blacks at Precious Metals.

* Pave' is translated from French - pavement set as in cobblestones.

Demand for coloured diamonds in Europe and America is outstripping supply, so prices are going through the roof. It is no surprise then that technology is being used to artificially create colours.

At the Las Vegas trade fair one trader had 30 beautiful colours, each available in any size, shape or consistently matched quantity. The colours were created with sophisticated high temperature, high pressure and irradiation processes.

Coincidently, at my Argyle cutter's office a few weeks later I met the founder of that company who joined us for lunch. He told me that he and a university professor experimented for years and perfected the colouring processes.

They can predict the colour change from low-quality less expensive diamonds. He uses this specialised knowledge to buy diamonds at cutting centres, and ships them to New York where the now wealthy professor treats them. This is "clean" business with no dangerous residual radiation and the stones are sold with the treatment declared. They supply large jewellery manufacturers with sets of diamonds that are sold with full disclosure.

Imagine this technology in the hands of less scrupulous people? Many Eastern European countries have turned their research facilities into diamond treatment businesses.

GE Bleached Pegasus Diamonds
Disclosure is an issue of great concern. General Electric Company has produced synthetic diamonds for industrial abrasives since 1955. In 1999 GE's research and development people discovered a way to improve the colour of some rare large diamonds (type II) using an advanced high pressure / high temperature treatment. The whitened gems more than doubled in value and are marketed as Pegasus diamonds.

The gem industry was confronted with an ethical dilemma. Legitimate gem dealers are required to disclose any treatments on invoices, but GE maintained the process duplicated nature and could never be detected thus disclosure was unnecessary. The issue would have remained un-resolved but for gemmologists discovering a number of tests to identify Pegasus diamonds.

Branding Gems

Access to technology in third world countries has led to an inevitable rise in the number of undisclosed treated gems.

Passing treated fancy coloured diamonds of as natural is a great way to turn a quick buck. Branding and independent certification of gemstones will become more common as a way of guaranteeing authenticity of untreated gems. Australia's Argyle Diamond Company was first to brand its diamonds by source. BHP are branding Yakuta diamonds from its new mine in Canada. They are inscribing a polar bear on the girdle or edge of diamonds that are cut and polished by locally trained Inuit workers.

De Beers too is re-inventing itself. It aims to establish a leak proof supplier of choice chain, eliminating "conflict diamonds" that have fuelled wars in Africa. The cutters De Beers supply will be encouraged to market and brand with the famous slogan "a diamond is forever". And for the first time ever De Beers itself will retail diamonds under its own name. They will be selling to their customer's customer's customers.