Head of sales at Rio Tinto, owners of Argyle, showing me Chow Tai Fook's jade and pink diamond necklace.

LONDON - Earlier this month, I paid a visit to a glittering one day exhibition of some of the rarest pink diamond jewellery on earth, held at the Orangery, Kensington Palace.

The largest pink diamonds are only around two carats, but they can fetch prices of up to 50 times those of white diamonds, often topping $1 million a carat.

With 42 jewels totalling 65 million dollars, all displayed in sumptuous showcases by the likes of Graff, Moussaieff, Chinese jewellery powerhouse Chow Tai Fook, Nirav Modi of Mumbai, and London and Sydney-based John Calleija, the event was an extremely glamorous affair.

Nirav Modi's 5.67 carat Pink Pear ring.

A showstopping necklace from Chow Tai Fook teamed jades with pink diamonds. Australian jewellers Mondial presented a daringly intricate blossom brooch in honour of the Queen's Jubilee - six leaves, two blossoms and 52 diamonds within the leaves allude to the date of the Queen's ascension to the throne. Graff showed a pink diamond teddy bear brooch – perhaps it’s unsurprising – Laurence Graff once told me his youngest client was a 3 month old baby whose parents had bought her a pink heart-shaped diamond. A bracelet by American jeweller LJ West featured rows of meticulously cut pink diamonds designed to attract both the maximum light and a buyer ready, willing and able to pay $8.8 million for the privelege of acquring it.

Diamond Jubilee Blossom brooch by Mondial Pink Diamond Atelier, Australia.

The Australian Argyle Diamond Mine produces 90 per cent of the world’s pink diamonds. Each year, it reserves its top 50 stones for the Argyle Pink Diamond Tender. This year 150 clients were invited to submit sealed bids following private viewings, sometimes lasting two hours in Perth, Hong Kong and – to celebrate the Queen’s diamond jubilee – London.

The Argyle Siren – the largest of three Fancy Vivid Purplish Pink diamonds larger than one carat and with clarity of VS2 or better ever to appear in almost three decades of the Argyle Pink Diamond Tender.

Pink diamonds have historically defied the recession. In 2010, Graff bought a pink diamond at Sotheby’s Geneva for a record-busting CHF45 million (US$45.6 million).

As I made my way back home from Kensington Palace in a chauffered Maserati courtesy of Argyle, it’s safe to assume those rare diamonds were about to begin their own journeys – into either investment portfolios or dazzling heirloom jewels.

Claire Adler writes on jewellery and watches for the Financial Times and Sotheby's. She consults as a writer and speaker for De Beers, Boodles and the World Gold Council.