This is the second instalment bringing you some facts and figures about some of the world’s largest and most valuable gemstones. The top six in reverse order…
6. Olympic Australis
The largest and most valuable opal was discovered in 1956 at the famous "Eight Mile" opal field in Coober Pedy, in South Australia. Named after a rather famous world sporting event that was taking place that year in Melbourne, the stone weighs in at 17,000 carats and is claimed to have 99% gem quality.
Due to the purity of the opal it is estimated that more than 7,000 carats could be cut from the piece. However the opal remains exactly as it was found.
Image shows from left: 125West Ruby, American Golden Topaz, Bahia Emerald
5. 125West Ruby
The 125West Ruby is currently the largest ruby in the world. This unique specimen is one of the world’s largest known rough ruby gemstones and weighs 8.2lbs or 18,696 carats. The ruby is semi-translucent to opaque and contains rutile, which may create a six-ray star if cut ‘en cabochon’ (i.e. polished but not faceted). The crystal displays a strong red fluorescence when exposed to long-wave ultraviolet light. It measures 122.4mm x 112.3mm x 133.9mm.
4. American Golden Topaz
The American Golden Topaz is the largest cut yellow topaz in the world. It is also considered as one of the largest faceted gemstones of any kind. It is an enormous cushion-cut stone weighing a staggering 4.5785kg which took a period of almost two years to cut and polish. The finished gemstone has 172 facets, with a pleasant light golden brown colour and almost flawless clarity and good transparency.
The gemstone, which is of Brazilian origin, is located in the Natural History Museum of the Smithsonian Institution, in Washington DC.
3. Carnaiba Emerald
Discovered in the 1970s, this emerald is considered as one of the largest in the world weighing 86,136 carats and is valued at over $1 million.
2. Chaiyo Ruby
This ruby is as famous for the mystery surrounding its origin as for the size of the stone itself. It weighs 109,000 carats - approximately three and a half stone, as much as the average seven or eight year old child. But there have been several claims that the stone is a fake. Experts supporting its validity believe that it came from Africa, yet the stone, which is valued at approximately £320 million, was once claimed to have been purchased from the Thai-Burmese border. Other theories name it as the object of a grand theft that was covered up as a result of military involvement.
Though we cannot know for sure, the most recent reports suggest that it is privately owned and held in a safety deposit box in Laos. Perhaps the intrigue has added to the value of this stone.
1. Bahia Emerald
The Bahia Emerald is the largest single cut emerald ever discovered. It weighs at a staggering 1.9 million carats and appraisals of the gem have valued it at over $900 million.
Over the last 61/2 years, nine men, one woman, three corporations and one government have laid claim to the giant emerald that’s been at the centre of a protracted ownership dispute in Los Angeles County Superior Court.
The case was finally concluded earlier this year when the court ruled that ownership was with a holding company owned by three businessmen, who claimed the emerald became theirs after it was put up as collateral in a $1.3 million deal for diamonds that ultimately fell through.
The Bahia Emerald was discovered on July 9th 2001 in the mine of Carnaiba, Brazil. The boulder-sized stone is one of the largest gems ever discovered.
It weights 38kg and has 180.000 carats spread in 9 crystals ranging in size from 220mm, 140, 130, 110 down to 37mm. Its known value is $372 million.
Research sources: Diamondrocks.co.uk; LA times .com; Jewelry-blog.internetstones.com