ARGYLE, Scotland, September 21 /PRNewswire/ --

- Vintage Year Produces Most Vivid Collection of Celebrities' Favourite
Diamonds

Diamond experts and high society figures across the globe are
preparing for the 23rd annual Rio Tinto Diamonds Argyle Pink Diamond Tender
held in Perth (September 11-14th 2007), Hong Kong (September 18th - 28th
2007) and New York (October 1st - 12th 2007).

The world's most exclusive diamond sale will feature 65 of the
world's rarest pink diamonds from the Argyle mine in Australia - the world's
main source of pink diamonds with an unparalleled depth of colour and
quality.

This year's Tender promises to be one of the most exciting to
date, with the Argyle Signature Stones possessing deeper and more vivid
colour intensity than previously seen in the Tenders. Spectacular purplish
reds, as well as stunning deep pinks and a rare grey-violet diamond are
included.

Excitement around the Pink Diamond Tender is understandable.
Since the first pink diamonds were recovered from the mine in 1985, demand
for these exceptional gems has attracted a cadre of elite and discrete
buyers. The pink diamond jewellery market is now worth hundreds of millions
of dollars as the desire to own the rarest has sent prices skyrocketing.

It is not unusual for pink diamonds to fetch more than
US$400,000 per carat. However, the sky is the limit when it comes to Rio
Tinto Diamonds' exclusive Signature Stones - each diamond is so unique that
it warrants an individual price tag.

To put the rarity of the Argyle Signature Stones into
perspective, Rio Tinto's Argyle mine produces on average 30 million carats of
rough diamonds a year. From this annual production only about 8,000 to 10,000
carats of polished pink diamonds are produced, of these a mere 65 carats are
deemed suitable for the Pink Diamond Tender.

Pink diamonds from the Argyle mine are dated at approximately
1.6 billion years old, but are predicted to run out by 2018. This forecast
has enhanced their exclusivity and image as a key investment option.

Despite demand, attendance to the Tender is restricted to
approximately one hundred key clientele from around the world who personally
view the diamonds in a secret location in Hong Kong, New York or Perth. Due
to the high security required for the Tender, the exact location is not
revealed to bidders until the very last minute. Bids are confidential and the
names of successful bidders and the values achieved are not disclosed. Those
that are successful will be notified personally in October.

Bidders expect only the best at Rio Tinto Diamonds' Argyle
Pink Tenders and that is exactly what they will get in the 2007 Pink Tender.
Commenting on the 2007 Tender, Jean-Marc Lieberherr, General Manager
Marketing, Rio Tinto Diamonds said, "What you see in the Pink Tender are some
of the rarest and most valuable gems in the world. Each Argyle Signature
Stone is unique and exquisite; if it doesn't have that 'wow' factor, it
doesn't make it into the collection."

"As far as pink diamonds are concerned, it's not about size
and clarity as it is for white diamonds: colour intensity is what matters.
The darker they are the more expensive they are, with the rare deep red the
ultimate prize. This year, the 65 Argyle Signature Stones we have selected
are deeper and more vivid than in previous years, this is an exciting and
valuable collection."