Bonhams has a rare treat lined up for jewellery connoisseurs, coming up in November.

“The most important set of Chameleon diamonds ever to be presented at auction leads the forthcoming Rare Jewels and Jadeite sale at Bonhams Hong Kong on 25 November,” the auction house announced. “The exquisite diamond necklace features nine Chameleon diamonds weighing 13.87 carats total and is expected to fetch between HK$ 1,600,000 and HK$ 3,000,000.”

Explains Bonhams Asia Director of Jewelry, Graeme Thompson: "Chameleon diamonds are amongst the rarest and most mysterious of coloured diamonds. Depending on temperature and light conditions, the diamond's colour transforms from "olive" green to a mesmerising brownish yellow or yellow.”

Thompson adds: "Due to their rarity, little gemmological information exists on Chameleon diamonds and scientists have yet to confirm the mechanism that causes their colour-changing behaviour. We are excited to present this extremely rare phenomenon in our upcoming sale."

Apart from this, the Hong Kong sale will also feature “an exceptional range of best-in-class diamonds, coloured gemstones, and signed jewellery”, Bonhams said.

The collection up for auction includes more than 150 lots with estimates ranging from HK$ 30,000 for a cultured pearl and diamond necklace, to HK$ 7,500,000 for the finest jade bangle to be offered at auction this year.

In addition to the Chameleon diamonds, there is a selection of other rare coloured diamonds on offer too: including an Intense Blue; three green diamonds; a 7-carat faint pink; and a striking collection of Vivid Yellows.

"Natural coloured diamonds can be found in almost every tone of the rainbow and can come in over 230 colour combinations,” Thomson explained. “They are formed when certain elements are captured within the diamond structure as it is forming from carbon atoms and this process can produce the breathtaking and rare colours we see.”   

Pic Cap: The Chameleon diamond necklace

Pic Courtesy Bonhams