Lot 617. An Impressive 73.23 carats Ceylon Royal Blue Sapphire and Diamond Necklace. Estimate HK$ 4.5 million - 5.5 million (€520,000 - 630,000). Photo: Bonhams.

The oval-cut sapphire, weighing 73.23 carats, within a pavé-set brilliant-cut diamond surround, suspended from an oval-link chain accented by similarly cut diamonds, diamonds approximately 25.00 carats total, necklace length 44.0cm, pendant length 5.8cm, pendant detachable 

Accompanied by a Gubelin report stating that the natural sapphire has no indications of heat treatment and originates from Sri Lanka (Ceylon). Report number 13116115, dated 22 November 2013.  

Also accompanied by an appendix stating that the sapphire possesses a richly saturated and homogeneous colour, combined with a high degree of transparency. Such a combination of characteristics is rare in natural sapphires of this size. 

Accompanied by a GRS report of Platinum Award stating that the natural sapphire is of vivid blue colour (GRS type 'royal blue') has no indication of thermal treatment and originates from Sri Lanka (Ceylon). Report number GRS2013-111548, dated 6 December 2013.  

Also accompanied by an appendix stating that the 'Royal Blue Sapphire' has extremely rare combination of size, excellent colour and good transparency.

Bonhams. AUCTION 23346: RARE JEWELS & JADEITE, 15:00 HKT - HONG KONG, ADMIRALTY