Chanthaboon, or today’s Chanthaburi province, is an area where ancient settlements were established in the prehistoric period. Then the “Chong,” a group of Mon-Khmer people, had settled down here before it developed into a town. Due to its abundant natural resources, Chanthaburi is famous for its fruits, Chanthaboon mats, and gemstones. 

The Origin of Chanthaburi Gemstones

            Chanthaburi’s gemstones started to gain a reputation when an ethnic group called the Gula or the Shan, who had expertise in gemstones, attempted to seek mineral veins from the north of Thailand to Cambodia. They found yellow and green sapphire with a combined shade of yellow and blue, as called by the natives as “Buddnamtaeng” at the hills called Khao Ploi Waen and Khao Wua in Chanthaburi. Therefore, they built a gemstone trading settlement during the era of King Rama V and trained the Chanthaburi people to polish gemstones since then.

Buddnamtaeng gemstone, image from www.ebay.com

A Man Named Sammuang

            After World War II, the local economy recovered, and gemstone trading in Chanthaburi was rapidly growing. An influx of people, most of whom were from the northeast, came searching for gemstone business opportunities in Chanthaburi. They worked as miners, polishers, and traders who sought rough stones for Chinese dealers in the market. These northeastern new rich increasingly gained influence in Chanthaburi. Meanwhile, a 30-year-old policeman named Sammuang retired from service after being suggested by his fellow policeman who retired previously to enter the gemstone industry. This friend gave advice and lent Sammuang money to start a business. However, since gemstone trading requires expertise and experience, a newcomer like Sammuang lost money in this business and eventually ran out of capital. 

From 50 Baht to Fortune

            With his last 50 baht, Sammuang decided to try his luck in Khao Wua. After walking halfway, he found a man aged around 60 years old digging gemstones in an old deposit. Everyone climbing this mountain could see it since it was a shallow hole being dug a long time ago. Sammuang asked if that old man had gemstones to sell, and he showed five small gemstones kept in a milk can, asking for a price of 50 baht. It was a difficult decision for Sammuang since it meant he had to spend all his money. “Just take them. They are not expensive at all,” the old man said. Thus, Sammuang decided to buy all five gemstones and walked for 4 to 5 kilometers from Khao Wua to the central rough stone market at the foot of Khao Ploi Waen. One of these gemstones was a high-grade blue sapphire worth 6,000 baht. When combined with the other four, the gemstones were sold for a total of almost 8,000 baht. Sammuang spent this money on cutting and polishing equipment and began learning about rough stones.

From Observations to the Invention of Heat Treatment

One day, Sammuang accidentally broke a star sapphire into two while polishing it. To have them combined is an expensive service so he came up with an idea to merge them using borax and heat. During the process, he observed that gemstones would gain more clarity when exposed to heat. Later in 1968, there was a large fire in Chanthaburi that took a few days to extinguish, bringing damage to various stores, including gemstone shops. Some fire-damaged stones were sold to Sammuang, and he noticed again that these gemstones were very clear. Therefore, he concluded that heat can change gemstone colors. He began experimenting by creating furnaces with different levels of heat. In the next step, he used fire-resistant cement, which was still in the testing phase and sponsored by the Siam Cement Group, to create a gemstone furnace fueled by coal. With this furnace, gemstones were heated to the point that opacity and inclusions disappeared, transforming them into stones with beautiful colors, resulting in the first successfully heated gemstone, which is a blue sapphire. However, there are no secrets in this world. The method of gemstone heat treatment gradually became known in the industry. Nevertheless, if it is not because Sammuang Kaewwaen invented the heat treatment, Chanthaburi might not be one of the world’s most important gemstone trading centers as it is today.

King of Orange Sapphire

Sammuang researched and developed his knowledge to create specific furnaces for each kind of gemstone. He found that the gas furnace can be used with gemstones in every color, on the condition that the level of heat must be adjusted to match each kind of them. The new opportunity arose when he bought Ceylon gemstones and heated them into yellow-orange and then dark orange. With research and financial support from his peers in the industry, he achieved success after three years of tremendous effort and traveled to America to present these yellow-orange stones to the market. He shared the details of heat treatment to persuade the American industry to accept heated gemstones. His heat treatment method attracted foreign gemmologists’ interest, and foreign reporters visited Chanthaburi to explore the truth about this method. As a result, Sammuang was named by a renowned American gemologist Cap Bisley as the King of Orange Sapphires. With Sammuang’s reputation, Thailand and Chanthaburi became widely known at the international level.

Sammuang’s photo from Metee Cheungsa-nguansit, and the image of orange sapphire from astrokapoor.com

            Since then, Thai dealers have sought rough stones from all over the world to be processed in heat treatment and then polished. This business generates a high level of employment and profit while making gemstones an important export product of Thailand and establishing its status as the world’s major gem and jewelry center. Although Sammuang passed away over a year ago, his spirit still lives on. “I hope that this knowledge will be transferred to later generations and become Chanthaburi’s and Thailand’s pride. Chanthaburi should be the center of the world’s gemstone trading,” he said. This dream is now a reality and this success will be forever cherished with gratitude towards his legacy.