Lot 9185. Fancy Deep Brownish Greenish Yellow Diamond, Conch Pearl, Gem Set and Diamond Brooch, Michael Youssoufian. Estimate 280,000 — 360,000 HKDLot Sold 600,000 HKD. Photo: Sotheby's. 

Of floral design, centring upon a cut-cornered square modified brilliant-cut fancy deep brownish greenish yellow diamond weighing 0.93 carat, surrounded by stamens set with diamonds of yellow tint, to the conch pearl petals framed by coloured sapphires, rubies and diamonds, completed by the diamond-set stem and pear-shaped emerald leaves, mounted in 18 karat white, yellow and pink gold, signed MY, with Michael Youssoufian maker's mark, pouch stamped M.Y.

Accompanied by GIA report numbered 11055835, dated 2 March 2000, stating that the 0.93 carat diamond is natural, Fancy Deep Brownish Greenish Yellow Colour; GIA further commented that 'the colour of this stone changes temporarily when gently heated, or when left in darkness for a period of time and is known in the trade as "CHAMELEON"'. Please note that the report is more than (10) years old and might require an update.

Sotheby's. Important Jewels and Jadeite, Hong Kong, 12 Oct 2017, 02:00 PM