Hong Kong – 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 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.

"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," explains Bonhams Asia Director of Jewellery, Graeme Thompson.

"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."

Lot 550. A Rare Fancy Coloured Diamond and Diamond Necklace. Estimate: HK$1,600,000.00 - 3,000,000.00 (€ 180,000 - 340,000). © Bonhams.

Accompanied by eight GIA reports stating that the 4.02 and 0.76 carat 'Chameleon' diamonds are Fancy Dark Gray-Greenish Yellow and Fancy Deep Grayish Yellowish Green colour, SI1 and SI2 clarity respectively; and the 2.18, 1.91, 1.26, 1.05, 1.01 and 0.98 carat 'Chameleon' diamonds are Fancy Dark Gray-Yellowish Green, Fancy Dark Gray-Greenish Yellow, Fancy Dark Grayish Yellowish Green, Fancy Dark Gray-Greenish Yellow, Fancy Deep Grayish Greenish Yellow and Fancy Deep Brownish Greenish Yellow colour. Reports dated 24 July 2012 to 17 November 2015. 

Also accompanied by an IGI report stating that the 0.70 carat diamond is Fancy Dark Grey Yellowish Green colour and VS1 clarity. Report number GT11799804, dated 7 August 2010. 

Also accompanied by a GIA Portrait Report entitled "The Chameleon Diamond Necklace" detailing this extraordinary phenomenon.

Alongside this piece, the Hong Kong sale features an exceptional range of best-in-class diamonds, coloured gemstones, and signed jewellery. There are 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.

Coloured Diamonds
In addition to the Chameleon diamonds, Bonhams presents a kaleidoscopic selection of rare coloured diamonds including an Intense Blue, three green diamonds, a 7 carat faint pink, and a striking collection of Vivid Yellows.

Highlight pieces include:

Lot 652. A 1.45 carat Natural Fancy Intense Blue diamond ring. Estimate HK$2,000,000 - $3,000,000 (€ 230,000 - 340,000). © Bonhams.

The marquise-cut fancy intense blue diamond, weighing 1.45 carats, between pavé-set brilliant-cut diamond shoulders of crossover design, to a plain hoop, ring size 5¼.

Lot 549. A 3.15 carat Natural Fancy Intense Yellowish Green diamond ring. Estimate HK$ 1,300,000 - 1,800,000 (€ 150,000 - 200,000). © Bonhams. 

The cushion-shaped fancy intense yellowish green diamond, weighing 3.15 carats, between heart-shaped diamond shoulders, weighing 0.43 and 0.41 carats respectively, ring size 5¾.

Accompanied by a GIA report stating that the 3.15 carat diamond is Fancy Intense Yellowish Green colour and VS2 clarity. Report number 6137892749, dated 8 January 2014.

Accompanied by two GIA reports stating that the 0.43 and 0.41 carat diamonds are both G colour and VS2 clarity. Report numbers 1162639182 and 5161639191, both dated 7 October 2014.

Lot 548. A 1.51 carat Natural Fancy Intense Pinkish Purple diamond ring. Estimate HK$2,000,000 -3,000,000 (€ 230,000 - 340,000). © Bonhams.

The cushion-shaped fancy intense pinkish purple diamond, weighing 1.51 carats, between bifurcated shoulders set with brilliant-cut diamonds, accented by similarly cut diamonds of yellow tint, ring size 4¼.

Accompanied by a GIA report stating that the diamond is Fancy Intense Pinkish Purple colour and VS2 clarity, with Excellent polish and symmetry and no fluorescence. Report number 2156254843, dated 1 August 2013.

Lot 546. A 1.24 carat Natural Fancy Intense Green diamond ring. Estimate HK$ 800,000 - 1,200,000 (€ 90,000 - 140,000). © Bonhams.

The rectangular mixed-cut fancy intense green diamond, weighing 1.24 carats, highlighted with brilliant-cut diamonds of pink tint, embellished by rose and brilliant-cut diamonds, between similarly cut diamond-set shoulders, remaining diamonds approximately 1.30 carats total, ring size 6¾.

Accompanied by a GIA report stating that the 1.24 carat diamond is Fancy Intense Green colour and SI1 clarity. Report number 2165064924, dated 14 April 2014.

"Natural coloured diamonds can be found in almost every tone of the rainbow and can come in over 230 colour combinations. 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." Thompson adds.

Jadeite
The sale headlines its jadeite selection with an exceptional jade bangle. Expected to fetch between HK$7,500,000 and HK$10,000,000, it is highly translucent with an intense to bright emerald green colour throughout.

"This bangle is the finest example to come to market this year that we know of, with its divinely rich colour and incredible translucency. We are delighted to be able to offer it," said Thompson.

Lot 647. An Exceptional Jadeite Bangle. Estimate HK$ 7,500,000 - 10,000,000 (€ 850,000 - 1,100,000). © Bonhams.

The highly translucent circular jadeite bangle of intense to bright emerald green colour throughout, the outer, inner diameter and thickness measuring 76.8 x 55.2 x 10.7mm.

Coloured Gemstones
The sale features an extensive but carefully curated selection of coloured gemstones including Kashmir Sapphires, Colombian Emeralds, Burmese Rubies, Sapphires, Spinels, Brazilian Paraiba Tourmaline and Sri Lankan. Padparadschas.

Highlights include:

Lot 646. A 5.02 carats Kashmir Sapphire and Diamond Ring. Estimate HK$ 2,500,000 - 3,500,000 (€ 280,000 - 400,000). © Bonhams.

The step-cut sapphire, weighing 5.02 carats, between tapered baguette and bullet-shaped diamond shoulders, diamonds approximately 1.20 carats total, maker's mark, ring size 5¼.

Accompanied by a SSEF report stating that the sapphire has no indications of heat treatment and originates from Kashmir. Report number 85940, dated 18 May 2016.

Accompanied by a Gubelin report stating that the sapphire has no indications of heat treatment and originates from Kashmir. Report number 16060103, dated 22 June 2016.

Lot 625. A 2.55 carats Kashmir Sapphire and Diamond Cluster Ring. Estimate HK$ 300,000 - 400,000 (€ 34,000 - 45,000). © Bonhams.

The cushion-shaped sapphire, weighing 2.55 carats, within a four-claw setting and a halo of brilliant-cut diamonds, extending to the shoulders, maker's mark, French assay mark, ring size 6.

Accompanied by a SSEF report stating that the sapphire has no indications of heat treatment and originates from Kashmir. Report number 92079, dated 30 May 2017.

Accompanied by a Gubelin report stating that the sapphire has no indications of heat treatment and originates from Kashmir. Report number 17040223, dated 3 May 2017.

Lot 563. A 1.82 carats Kashmir Sapphire and Diamond Ring. Estimate HK$ 130,000 - 200,000 (€ 15,000 - 23,000). © Bonhams.

The step-cut sapphire, weighing 1.82 carats, between triangular-shaped diamonds, to a plain hoop, ring size 6¼.

Accompanied by a SSEF report stating that the sapphire has no indications of heat treatment and originates from Kashmir. Report number 97728, dated 7 February 2018. 

Lot 644. A 4.35 carat Colombia No-Oil Emerald and diamond ring. Estimate HK$750,000-1,500,000 (€ 260,000 - 370,000). © Bonhams.

The oval-cut emerald, weighing 21.96 carats, within a four double-claw setting and a two tier surround of marquise-cut diamonds, accented by brilliant-cut diamonds on the gallery and shoulders, diamonds approximately 6.15 carats total, ring size 6¾.

Accompanied by an AGL (American Gemological Laboratories) report stating that the emerald has indications of minor clarity enhancement and originates from Colombia. Report number 1091794, dated 18 April 2018. 

Accompanied by a GRS report stating that the emerald is vivid green colour, has indications of insignificant clarity enhancement and originates from Colombia. Report number GRS2017-118653, dated 21 November 2017.

Lot 629. A pair of Colombian No-Oil earrings at 3.91 and 4.48 carat. Estimate HK$1,300,000-2,300,000 (€ 150,000 - 260,000). © Bonhams.

The step-cut emeralds, weighing 4.48 and 3.91 carats, each within a double four-claw setting surrounded by pear and marquise-cut diamonds, suspended from a cluster surmount set with brilliant, pear and marquise-cut diamonds, diamonds approximately 9.50 carats total, length 3.6cm.

Accompanied by two AGL (American Gemological Laboratories) reports stating that the emeralds have no indications of clarity enhancement and originate from Colombia. Report number 1092645 and 1089672, dated 6 July 2018 and 21 February 2018.

Accompanied by two GRS reports stating that the emeralds have no indications of clarity enhancement and originate from Colombia. Report numbers GRS2018-026627 and GRS2017-118451, dated 8 February 2018 and 16 November 2017. Plus two appendices referring to emeralds as "Old Mine".

Lot 645. A 4.02 carat Burma No Heat 'Pigeon's Blood' Ruby and diamond ring. Estimate HK$4,800,000-6,800,000 (€ 540,000 - 770,000). © Bonhams.

The oval-cut ruby, weighing 4.02 carats, within a four-claw setting and a surround of brilliant-cut diamonds, extending to the shoulders, diamonds approximately 3.35 carats total, ring size 5¾.

Accompanied by a SSEF report stating that the ruby is 'pigeon blood red' colour, has no indications of clarity enhancement and originates from Burma (Myanmar). Report number 102866, dated 20 September 2018. 

Accompanied by a Gubelin report stating that the ruby is 'pigeon blood red' colour, has no indications of clarity enhancement and originates from Burma (Myanmar). Report number 18027074, dated 28 February 2018. Also accompanied by a Gubelin Information Sheet on the rarity of unheated rubies. 

Accompanied by ten GIA reports stating that all ten diamonds weigh 0.30 carats and are all D colour and VVS1 clarity. Reports dated 11 April to 9 August 2018.

Lot 591. A 6.40 carat natural unheated Brazilian Paraiba tourmaline and Diamond Ring BY MQ GEM. Estimate HK$ 1,750,000 - 3,000,000 (€ 200,000 - 340,000). © Bonhams.

The oval-cut Paraiba tourmaline, weighing 6.40 carats, to a four-claw setting, within a double surround of pear and brilliant-cut diamonds, to an undulating pierced hoop highlighted with brilliant-cut diamonds, diamonds approximately 5.00 carats total, ring size 6½.

Accompanied by a SSEF report stating that the 6.40 carat Paraiba tourmaline has no indications of heat treatment and originates from Brazil. Report number 94909, dated 28 August 2017. 

Accompanied by a GRS report stating that the Paraiba tourmaline has no indications of thermal treatment and originates from Brazil. Report number GRS2017-071947, dated 18th July 2017.

Lot 572. A collection of 32 Natural Burmese Unheated Spinels from Mogok set in mother-of-pearl as an impressive necklace, bracelet, earring and ring suite. Estimate HK$1,500,000-2,000,000 (€ 170,000 - 230,000). © Bonhams.

The necklace comprising nineteen antique cushion-shaped spinels, each embedded in a polished mother-of-pearl plaque, within a surround of brilliant-cut diamonds; the bracelet, earrings and ring en suite, diamonds approximately 16.25 carats total, spinels 62.66 carats total (including ring, 6.57 carats), lengths: necklace 41.0cm, bracelet 17.8cm, earrings 4.8cm, ring size 6¼(4).

Accompanied by two SSEF reports stating that 1) the thirty-one spinels (necklace, bracelet, earrings) have no indications of heat treatment and originate from Burma (Myanmar) and 2) the 6.57 carat spinel (ring) shows no indications of treatment and originates from Burma (Myanmar). Report numbers 101091 and 101010, dated 28 and 26 June 2018 respectively.

Also accompanied by a premium appendix stating that the spinels possess extraordinary characteristics and merit special mention and appreciation.

Their attractive and vivid red colour is due to a combination of well-balanced trace elements which are characteristic for the finest spinels from Mogok in Burma (Myanmar). Assembling a matching selection of natural spinels from Burma of this size and colour can be considered rare and exceptional.

Signed Jewellery
Reflecting the ever-growing market interest in signed jewellery, Bonhams features an exquisite range of signed jewellery in this sale with a selection from the important Houses including Bulgari, Cartier, Chaumet, Graff, Harry Winston and Van Cleef & Arpels as well as from contemporary designers such as Alexander Laut.

Highlights include:

Lot 643. An exceptional necklace and earring suite by Bulgari. Estimate HK$4,700,000-6,000,000 (€ 530,000 - 760,000). © Bonhams.

The articulated necklace set with sixteen oval-cut diamonds, weighing 40.08 carats total, each within a four-claw setting highlighted to each side with pairs of fancy-cut diamonds, connected by undulating links pavé-set with brilliant-cut diamonds, the pair of earrings en suite, each set with an oval-cut diamond, weighing 2.12 and 2.06 carats, remaining diamonds approximately 30.25 carats total, both signed Bulgari, necklace inner circumstance 39.5cm, earring length 1.9cm, original case.

Accompanied by twelve GIA reports stating that the diamonds are G-I colour, IF-SI1 clarity. Reports dated 27 April 1995 to 28 May 1997. 

Accompanied by an IGI report stating that the 2.01 carat diamond is H colour, VS1 clarity. Report number 2670107, dated 21 April 1997.

Lot 649. A Natural Fancy Vivid Yellow internally flawless diamond ring weighing 5.64 carats by Cartier. Estimate HK$3,000,000-4,000,000 (€ 340,000 - 450,000). © Bonhams.

The step-cut fancy vivid yellow diamond, weighing 5.64 carats, between step-cut diamond shoulders, remaining diamonds approximately 2.00 carats total, signed Cartier, numbered, ring size 5¾.

Accompanied by a GIA report stating that the diamond is Fancy Vivid Yellow colour and Internally Flawless clarity. Report number 10909860, dated 21 August 2018. 

Accompanied by two GIA reports stating that the 1.03 carat and 1.05 carat diamonds are both D colour and both VVS2 clarity. Report numbers 6197556751 and 2191556604, both dated 6 August 2018. 

Also accompanied by a photocopy of the original Cartier receipt from the Cartier boutique at 2 East 52nd Street, New York, NY 10022, showing a purchase amount of US$583,000. Receipt number 7235892, dated 21 March 2001.

Lot 650. An exceptional Diamond and Coloured Diamond pendant necklace with a 5.93 D IF Type IIa pear-shape and 2.55 carat Natural Fancy Vivid Orange Yellow pear-shape diamond, by Cartier. Estimate HK$3,500,000-5,500,000 (€ 400,000 - 620,000). © Bonhams.

The pear-shaped diamond, weighing 5.93 carats, suspended from a similarly-cut vivid Orangy Yellow diamond weighing 2.55 carats and three brilliant-cut diamonds, two of yellow tint, all connecting to a brilliant diamond weighing 2.37 carats and curb-link neckchain highlighted with matching brilliant-cut diamonds, remaining diamonds approximately 5.05 carats total, signed Cartier, numbered, maker's marks, French assay marks, pendants detachable, pendent length 4.9cm, neckchain length 38.1cm.

Accompanied by a GIA report stating that 5.93 carat diamond is D colour and Internally Flawless clarity. Report number 2195149158, dated 25 July 2018. 

Accompanied by a GIA report stating that 2.37 carat diamond is D colour and Internally Flawless clarity, with Excellent Cut, Polish, and Symmetry. Report number 2191570247, dated 10 August 2018. 

Both accompanied by an appendix from GIA stating that the diamonds are Type IIa and therefore chemically pure. 

Accompanied by a GIA report stating that 2.55 carat diamond is Fancy Vivid Orangy Yellow colour. Report number 10601920, dated 2 March 2018.

Lot 615. A Jadeite 'Alhambra' necklace, by Van Cleef and Arpels. Estimate HK$150,000-200,000 (€ 17,000 - 23,000). © Bonhams.

Comprising a series of twenty clover-shaped, translucent and light green jadeite links, with ropetwist detail, signed V.C.A., numbered, maker's marks, French assay marks, length 82.0cm.

Accompanied by a Hong Kong Jade & Stone Laboratory report stating that the selected natural colour fei cui (jadeite jade) has no resin detected. Report number KJ 99103, dated 10 October 2018.

Lot 617. A Ruby and Diamond bracelet, by Van Cleef and Arpels circa 1965. Estimate HK$280,000-380,000 (€ 32,000 - 43,000). © Bonhams.

The highly articulated bracelet set throughout with circular-cut rubies, intersected by diagonal rows of brilliant-cut diamonds, diamonds approximately 5.90 carats total, rubies approximately 19.50 carats total, signed Van Cleef & Arpels, maker's mark, numbered, French assay mark, length 17.8cm.

Lot 648. A 5.04 carat D IF Type IIa pear-shape diamond ring circa 1955, by Harry Winston. Estimate HK$2,000,000-3,000,000 (€ 230,000 - 340,000). © Bonhams.

The pear-shaped diamond, weighing 5.04 carats, between tapered baguette-cut diamond shoulders, signed Winston, ring size 5½, original case.

Accompanied by a GIA report stating that the 5.04 carat diamond is D colour and Internally Flawless clarity. Report number 41061, dated 24 January 2017. 

Also accompanied by a GIA type classification letter, dated 24 January 2017, stating that the diamond is Type IIa, therefore chemically pure.

The sale also highlights a range of motif brooches including: 

Lot 568. A Diamond, Burmese Mogok "pigeon blood red" Ruby, Emerald, Sapphire and Lapis Lazuli kingfisher brooch by Cartier. Estimate HK$180,000-280,000 (€ 20,000 - 32,000).© Bonhams.

Modelled as a kingfisher with a polished beak, the head pavé-set with brilliant-cut diamonds, the eye set with a cushion-shaped ruby, weighing 0.68 carats, the crest with calibré-cut rubies, emeralds and sapphires, to a polished pear-shaped lapis lazuli body, issuing a feathered tail of calibré-cut sapphires, perched on a branch, diamonds approximately 1.25 carats total, signed Cartier, numbered, lapis lazuli later replaced, length 6.7cm.

Accompanied by a Gubelin report stating that the 0.68 carat ruby has no indications of heating, is "pigeon blood red" in colour and originates from Burma (Myanmar). Report number 18091066 dated 2 October 2018.

Also accompanied by an Information Sheet issued by Gubelin entitled "Rubies From Mogok, Burma".

Lot 569. A Ruby, Sapphire,Turquoise and Diamond exotic bird brooch, by Chaumet, circa 1960. Estimate HK$80,000-120,000 (€ 9,000 - 14,000). © Bonhams.

Designed as a stylised bird-of-paradise, the head set with a cabochon ruby, polished beak and turquoise crest, the eye with a marquise-cut diamond, the neck of rope-twist detail, highlighted to the underside with brilliant-cut diamonds, the body and textured wings set with circular-cut sapphires, rubies and a cabochon turquoise, issuing an articulated chevron-link tassel, signed Chaumet, numbered, maker's mark, French assay marks, length 9.0cm.

Lot 557. A Diamond and Coloured Diamond Novelty flower brooch, by Chaumet. Estimate HK$100,000-200,000 (€ 11,000 - 23,000). © Bonhams.

Modelled as a lily, pavé-set throughout with brilliant-cut diamonds, some of yellow and pink tint, issuing marquise-shaped diamond stamen of similar hue, diamonds approximately 6.00 carats total, signed Chaumet Paris, numbered, maker's mark, French assay marks, length 7.2cm.

Lot 560. A pair of winking cat Ruby, Diamond and Turquoise novelty brooches. Estimate HK$ 40,000 - 60,000 (€ 4,500 - 6,800). © Bonhams.

Each designed as a winking cat with a circular-cut ruby eye, highlighted by single-cut diamonds, above elongated whiskers and a cabochon turquoise body, the tail of engraved detail, French assay marks, lengths 5.0cm and 4.6cm.

Lot 566. An early 20th century Emerald Diamond and Pearl brooch-pendant, circa 1900. Estimate HK$65,000-85,000 (€ 7,300 - 9,600). © Bonhams.

Of cartouche design, centrally set with a step-cut emerald, clustered by old brilliant-cut diamonds within a scrolling floral surround of old brilliant, single and rose-cut diamonds, suspending a drop-shaped pearl measuring 10.9 x 8.4 x 7.8mm, diamonds approximately 3.65 carats total, emerald approximately 1.40 carats, brooch attachable to become a pendant, width 5.9cm.

Lot 573. A Lapis Lazuli and Diamond butterfly brooch by Van Cleef & Arpels. Estimate HK$75,000-100,000 (€ 8,500 - 11,000). © Bonhams.

Designed as a butterfly, the wings comprising four plaques of lapis lazuli, each within a beaded border, the navette-shaped body set with three brilliant-cut diamonds, signed VCA, numbered, French assay mark, maker's mark, length 4.5cm, width 5.5cm.