Knowledge
Siam, or Thailand as it has been known since 1939, has long been an important historic source of rubies. Producing fine gemstones for hundreds of years, these old mines also helped establish Thailand as a major centre for gem trading and cutting, which continues through to today.
Gemstones
The Historic Siam Mines
An iron rich area covering parts of Thailand and its border with Cambodia, has been a known source of rubies for over 600 years. It was in 1408, when rubies were first mentioned in an account by Chinese traveller Ma Huan, who described the stones ‘bright and clear like the seeds of the pomegranate.’
Over the next three centuries European travellers embarked on journeys to Thailand, also writing of these historic mines and the abundance of rubies which could be found, especially in the Chanthaburi province. This was to become the largest source of fine quality ruby in Thailand.
Throughout these early years of exploration, gems were known to be found in this region, and Simon de la Loubère , the French envoy to Siam in 1687 noted that these stones often found their way into the possession of monks, who used them as charms.
It was nearly two centuries later, in 1857, that the Chanthaburi mines were rediscovered by Shan traders from Mogok, who leased the mines off the government and brought in workers from Burma. This set off an incredible gem rush in the country, and whilst this still continues today, it was not so lucrative initially. In 1880, Mong Keng took the monopoly of the mines and made them a success, becoming known as the ‘King of Precious Stones’ in the process.
Not long after, in the 1890s, the English company ‘The Sapphires and Rubies of Siam, Ltd’ obtained the rights to mine in the country, as did ‘Siam Exploring Co. Ltd. However in 1919 the Siam Mining Act restricted who could extract gems, with none of these ventures proving successful in the long term.
It wasn’t until nearly half a century later in the 1960s when ruby production had declined in other countries that mining made an industrial scale comeback in Thailand, the only other large source of fine, facetable ruby at the time. By the 1980s, it had become the major source of rubies globally.
As of the late 1990s, the majority of the Thai mines have been exhausted, but the area remains one of the most important gem trading locations in the world, its reputation having been firmly established throughout history.
Characteristics of a Siam/Thai Ruby
Formed in a basaltic deposit, these rubies have a high iron content which causes an elegant darker red hue, with purple and brown tones. The fluorescence of a Thai ruby is masked by its chemical makeup, thus the glow that can be seen in Burmese rubies is not present.
Siam rubies are also known for their absence of rutile silk, which means that star rubies cannot be produced in this locality.
The Value of a Siam/Thai Ruby
Thai rubies have held their value for many years and with their beautiful darker colouration they are often highly coveted. Value is also determined by the size and quality of each individual stone, so there can be much variation.
£7,600
£5,100
£13,200
£3,600
£11,000
The Berganza collection features a wonderful selection of these rubies dating back to the Victorian era. Ruby and diamond cluster rings with silver settings showcase the deep hue of these gemstones perfectly and would make for a truly elegant right hand ring.
Fabulous engagement rings from the early 1900’s also showcase fine Siam rubies, often with several perfectly matching stones to create one stunning design.
Moving forwards to the latter half of the 20th century and some of our most remarkable cocktail rings feature Thai rubies. Big and bold pieces with impressively sized gems, these rings are the perfect accessory to make a statement with!
Burma Rubies
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Mozambique Rubies
Zambian Emeralds
Colombian Emeralds
Yes, measuring a 9 on the Mohs scale, Thai rubies are one of the hardest gemstones and can be worn and enjoyed regularly.
Ruby mining in Thailand peaked in the 1980s and the mines have since been largely depleted with most mining activity now occurring in neighbouring Cambodia.
Treating rubies is a common occurrence today, and Thai rubies are often treated to improve their colour and remove unwanted undertones. To know whether your ruby has been enhanced we would recommend taking it to a reputable gemmologist or laboratory for them to assess.
