Blue diaonds @ Sotheby's. Jewels: The Hong Kong Sale. 1 June 2010. Hong Kong

A stunning pair of coloured diamond and diamond ear pendants. photo Sotheby's

Each set with a heart-shaped fancy deep blue diamond weighing 2.48 and 2.03 carats, suspending a detachable pear-shaped diamond weighing 10.12 and 9.64 carats, mounted in platinum, 3.0 cm long - Estimate. HK$28,800,000 - HK$38,800,000 Price Realized HK$34,260,000 ($4,416,306)

Accompanied by four reports dated from 6 March 2007 to 3 June 2008 from the Gemological Institute of America with the following details:

Report Date Weight Colour Clarity

10454112 03/06/08 10.12 D VS2
16948833 07/04/08 9.64 E VS1
16160884 18/06/07 2.48 Fancy Deep Blue VS2
11205394 06/03/07 2.03 Fancy Deep Blue IF

Also accompanied by two supplemental letters by the Gemological Institute of America stating the 2.48 and 2.03 carat diamonds have been determined to be a type IIb. Type IIb diamonds are very rare in nature (from the laboratory's experience, less than one half of one percent) and contain small amounts of boron that can give rise to a blue or gray colouration. An unusual property of type IIb diamonds is that they are semi-conductors and conduct electricity. Historically, the ancient mines of India produced occasional blue diamonds but today the most significant source is limited to the Cullinan (formerly Premier) Mine in South Africa.

Among famous gem diamonds, the 70.21 carat Idol's Eye and the 45.52 carat Hope are examples of type IIb (2)

2.48 2.03克拉心形深藍色鑽石10.12 9.64克拉梨形足色VS2 E/VS1鑽石耳環一對

An important coloured diamond and diamond ring. photo Sotheby's

Set with a heart-shaped fancy deep blue diamond weighing 2.88 carats, flanked by two triangular-shaped intense and vivid pink diamonds weighing 0.21 and 0.20 carat, within a pavé-set diamond two-tiered surround and half-hoop, mounted in 18k rose gold, ring size 5½ - Estimate HK$12,500,000 - HK$20,000,000 Price Realized HK$12,980,000 ($1,673,195)

Accompanied by report no. 17227452 dated 29 July 2008 from the Gemological Institute of America stating that the 2.88 carat diamond is fancy deep blue, natural colour, internally flawless clarity

2.88克拉心形深藍色全美鑽石鑽石戒指

A coloured diamond and diamond ring by Van Cleef & Arpels. photo Sotheby's

Set with a marquise-cut fancy blue diamond weighing 2.00 carats, flanked on either side by three-rows of tapered baguette-cut diamonds, mounted in platinum, ring size 5¼, with French assay mark for platinum, in light green leather Van Cleef & Arpels case. With maker's mark for Van Cleef & Arpels, No. S15668. Estimate HK$640,000 - HK$950,000 Price Realized HK$2,420,000 ($311,952)
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Accompanied by a certificate of guarantee from Van Cleef & Arpels

Also accompanied by report no. 6117769222 dated 10 March 2010 from the Gemological Institute of America stating that the 2.00 carat diamond is fancy blue, natural colour, VVS1 clarity

2.00克拉欖尖形藍色VVS1鑽石鑽石戒指 Van Cleef & Arpels設計

A coloured diamond and diamond ring by Suwa. photo Sotheby's

Designed as a cluster of vari-sized marquise-cut diamonds, accented by a pear-shaped fancy intense blue diamond weighing 1.25 carats, mounted in platinum, ring size 5¾, in black leather Suwa case. Signed Suwa, No. 109X4. Estimate HK$1,050,000 - HK$2,000,000 Price Realized HK$1,820,000 ($234,608)

Accompanied by report no. 15122499 dated 7 March 2008 from the Gemological Institute of America stating that the 1.25 carat diamond is fancy intense blue, natural colour, VS1 clarity

Also accompanied by a supplemental letter by the Gemological Institute of America stating the 1.25 carat diamond has been determined to be a type IIb. Type IIb diamonds are very rare in nature (from the laboratory's experience, less than one half of one percent) and contain small amounts of boron that can give rise to a blue or gray colouration. An unusual property of type IIb diamonds is that they are semi-conductors and conduct electricity. Historically, the ancient mines of India produced occasional blue diamonds but today the most significant source is limited to the Cullinan (formerly Premier) Mine in South Africa.

Among famous gem diamonds, the 70.21 carat Idol's Eye and the 45.52 carat Hope are examples of type IIb

1.25克拉梨形濃藍色VS1鑽石鑽石戒指Suwa設計

Sotheby's. Jewels: The Hong Kong Sale. 1 June 2010. Hong Kong www.sothebys.com