The largest ever 'perfect' diamond believed to be worth as much as £16 million has arrived in London ahead of its spring auction in New York.
It is considered to be internally flawless in appearance, the 100-carat diamond is in London for a one-day viewing ahead of Valentine's weekend.
According to Sotheby's, it joins an exclusive club of only five diamonds of similar quality, which weigh more than 100 carats, ever to be sold worldwide.
This diamond is the definition of perfection. The colour is whiter than white, it is free of any internal imperfections, and so transparent that I can only compare it to a pool of icy water. It is the first true emerald-cut diamond over 100 carats to be offered at auction - the most classic of cuts, quietly elegant and very contemporary.
Originally uncovered in southern Africa, the stone weighed more than 200 carats before being meticulously refined to 100.20 carats by its current owner.
Sotheby's hosted the stunning emerald-cut gemstone in its New Bond Street Gallery today and it is scheduled to appear in Dubai, Los Angeles, Hong Kong and Doha.
After completing its world tour, it will be auctioned in New York on April 21, where it is expected to fetch between 19 and 25 million US dollars (£12.4m to £16.3m) - more than 150,000 US dollars per carat (£98,000).
Lisa Hubbard, chair of North & South America for Sotheby's international jewellery division, said: "The rarest object of natural beauty on the market right now, this 100-carat diamond could be considered the ultimate acquisition.
"The stone gives you so many options - admire it un-mounted, wear it as a simple but stunning pendant, or mount in a designed jewel."