The kingdom of gemstones

A country of constant discovery.

While gems have been mined in Cambodia for centuries, it is a land that has seen little peace over the years. Since the time of the kings of Angkor, Cambodia and its Khmer people have been claimed by Vietnam, Thailand and France. These upheavals of politics interrupted the production of precious stones intermittently and left the details of mining locations and history difficult to determine.

Thankfully, Cambodia is now at peace and it is safe to travel throughout the country. I have made two extended expeditions from the new aquamarine pegmatite mines in Takeo to the famous zircon mines in Ratanakiri. This would not have been possible without the help of Mr. Votha Un who acted as my guide/interpreter. Neither of us had travelled to many of these areas and it was a great experience to explore them together.

There is much misinformation about what is currently happening in Cambodia. My visits were both in 2007 and I can only speak about what I have seen first hand. I know that the government is trying to reduce illegal mining and enforce more strict environmental regulations than in the time of the Khmer Rouge. This has slowed the issuing of new mining permits for gems. However, a few mining entities have requests and environmental impact statements in the works, so maybe another boom is coming!

Cambodia is passing through a window of its development that is perfect for the gem adventurer. There are many things to discover without being so far out of reach to be extremely dangerous, expensive or time consuming. The people are friendly, the food is good, and the weather is warm. Transportation and roads continue to improve. Votha and I did all of our traveling in his Toyota Camry or on the small 125 cc motorcycles that are so abundant in southeast Asia.

If you are looking for a place to explore, Cambodia is the perfect blend of adventure and comfort. Not only does this country have gems of the mineral variety, it has world renowned monuments of its glorious history and unique endangered species. Sometimes, these are found side-by-side. Soon this country will become similar to Thailand and no longer be the wild East. Cambodia has already made so many changes since my first trip nearly a decade ago. Sooner is better for those who would like to feel a sense of the Cambodia that was hidden away for decades. Another decade, and the generation that has lived through unbearable times will be gone.
Gem mining in Cambodia
 1. Pailin
A legendary source of ruby and sapphire

Pailin, located in eastern Cambodia along the border with Thailand, is the most famous of the gem mining areas in this country. Legend says that precious stones were first discovered here by Burmese traders observing river otters playing with the rough gems. The word Pailin, in fact, means otters (pai) playing (lin).  Pailin has been a source of blue sapphires for so long that the Thai word for blue sapphire is, in fact, also pailin!

The first written record of the gem trade dates back to the 1400’s when a Chinese trader by the name of Ma Huan mentions them in his writings. For a time near the end of the 19th century, the area around Pailin produced most of the world’s supply of sapphires. This area was again an important source of ruby and sapphire during the time of the Khmer Rouge (KR). The KR government allowed Thai miners to operate mechanized mines throughout the area.

The stones are recovered from alluvium of weathered basalt by trommels and jigs in the case of large operations or by simple sieving by hand. The area around Pailin produces blue sapphires while further south, Samlot produces rubies. These stones have the same genesis as those across the border in Thailand in places such as Bo Rai. This means that they have relatively high iron content compared to metamorphic stones from Burma (Myanmar).

 Pailin was, for the most part, closed to outsiders throughout the 1980’s and 1990’s. Now the border is open and easy to cross by land. You can get to Pailin from within Cambodia of course, but for those living or studying in Bangkok, it is much easier to arrive via Chantaburi, Thailand. Once in Chantaburi, you can arrange for a songtheaw (taxi) to take you to the border. The price will vary of course, but a one-way ride should cost about 800 Baht for the entire vehicle.

When traveling from Chantaburi, you will cross the border at Pong Nam Ron on the Thai side. The town on the Cambodian side is Prum. You must bring passport photos and 1000 Baht for your visa. The ride from Prum to Pailin is about 15 km, so you again will need to arrange for a taxi to get you to town. It is not likely that you would need hotel reservations, but you will need a guide to take you around.

 AIGS students have been using Mr. Votha Un as the local guide for the past few years. Votha speaks very good English and even worked as a gem dealer for a time. I have traveled all over Cambodia with him and he is a very easy person to get along with. He can be contacted by e-mail to make arrangements for a tour.

The mining in and around Pailin varies with the amount of government oversight, weather and harvest season. Many of the miners don’t really make any money, but they seem to enjoy mining for fun just as hobbiests looking for gold. Gemstone enthusiasts can sure understand the mentality!


A reliable place to find people hand-mining is along the Bourtang Sou River. Other villages around Pailin such as Toul Leae (12° 52.661N by 102° 34.932) and Ou Tavau (12° 50.559N by 102° 37.044E) produce some sapphires. Most areas have been already worked by the Thai during the time of the Khmer Rouge thus leaving very little for the locals to find.


Samlot is a ruby mining area about fifteen miles southeast of Pailin. Again, this was an area heavily worked by the Thais. The jungle has reclaimed many of the old mines, but in some areas the old equipment still remains. Today there are a few miners working the old tailings by hand. I have seen very nice stones of two carats said to be from Samlot, but during our visit, we did not see anything cuttable.



In 2006, Ultra Marine Kiri (Cambodia) Ltd. received a license to mine the Sen Chauv area of Samlot. However, there was no sign of mechanized mining in November 2007 and the locals did not mention anything. As of 2005, Jirech International Cambodia Construction and Import-Export Co. Ltd. had received a concession for mining but was in the process of preparing an environmental impact assessment.

Another company, Sonuba Cham Industries Co. Ltd., had also received a concession in 2005. They would like to mine in the Phnom Trop area in Pailin city. They too are preparing an environmental assessment. So it seems for now that all mining in the Pailin District will remain small. Maybe before the end of the decade we will once again see fine rubies and sapphires extracted from previously unexploited areas.

2. Ratanakiri
The best blue zircon

The blue zircons of Bokheo are the finest in the world. Only the stones from this area of northern Cambodia seem to acquire the intense blue colors that make them so famous. Across the nearby Vietnamese border, the stones just don’t seem to be able to get the same intensity.

Highway 7 from Phnom Penh to Stung Treng is paved and in good to great shape. A dirt road connects Highway 7 to Ban Lung (the capitol of the Ratanakiri Province). This road varies from good in the dry season to very bad in the wet season. Of course, I decided to visit Ratanikiri in the wet season and it was a long bumpy ride from the highway to Ban Lung. It is possible to fly into Ban Lung from Phnom Penh, but only in the dry season. This would be our base from which we would make our day trips to the mines.

While in Ban Lung, we stayed at the new and comfortable Kim Morakat Hotel. This hotel is located in town making it easy to walk through the markets and gem shops. I was surprised to see just how much fine quality cut zircon was available. Actually, I had never seen such good stones and never realized that zircon could be heated to such attractive colors. This trip was going to be a real learning experience!

Our first day out was our longest. In order to be back to town and avoid the afternoon rains, we had to be moving by 6 AM. This day Votha drove is car to Bokheo. This was no easy task as the road was in hideous shape. Amazingly, Votha was able to maneuver his car past the huge ruts and potholes. We were only high-centered a couple of times. Thankfully a Toyota Camry is not too heavy. The sixteen mile trip took about an hour and fifteen minutes each way.

In Bokheo we rented motorcycles and drivers that took us far out to a mining area that was producing stone that could be heated to an excellent color. The one-hour motorcycle ride took us down an impassable road and onto tracks into the jungle. Once we ran out of track, it was a twenty minute hike to the mine on the far side of Boloy mountain, where we found a group of miners working the slopes.

 Our stay only lasted a few minutes as we had to begin the long trek back to Ban Lung. This was the most brutal day of the trip. The small motorcycles are not meant to carry two people across the terrain we traversed. My back would ache for the remainder of the trip. I guess it was a way to remind me that we had really been somewhere!

On the way back to Bokheo, we made a quick stop at a mining village just outside of town (13° 42.081N by 107° 11.752E). Here the miners would dig a vertical shaft about a meter in diameter and up to ten meters deep. The soil brought up would be sifted by hand for any stones. Horizontal shafts are dug when paydirt has been reached. This is the same technique seen all over the world when hand miners dig in dry alluvium/eluvium.

Back in Bokheo, we were offered low quality small crystals for about $20 per kilo. These would have been good for inclusion studies, but very few would have produced anything cuttable. We were told that there were other mines around, but they would be even more difficult to reach. The wise advice of the locals was to visit in the dry season!

I had purchased some rough from the miners that day. Once we had cleaned ourselves up from the long day, we headed out to see if we could find someone who would cook our stones for us. There are only a few stone heaters in the city and most of them wanted quite a lot for the service. Finally, we met Mr. Chhor Hour Kruy who was willing to help us with our project.

Mr. Kruy had been a gem dealer for many years and heating zircons for a dozen. We had “discovered” him through his wife who has a shop in the central market. I did not want to heat my rough that night since the quote was for treating 500 grams of rough and I was well below this quantity.

The next day, we again left early in the morning. This time we slept in a bit and did not leave until 6:30 AM. On this day, we started from Ban Lung on motorcycles. Our destination was the village of Baesrak (13° 36.880N by 107° 04.627E). This was a relatively new are for mining zircon, but it was producing quite a few stones.

 This time our route was not as brutal as the day before. However, it was far from smooth. My back was already hurting from the pounding of the previous day. We had not been able to locate any larger motorcycles, so we again stuck with the little ones. The route was generally more level on this day, so we could travel at a higher speed. The drawback to traveling at high speed was that when we hit a hole - it hurt a lot!

 One of the bikes had a flat as we approached a small village. This gave us a break while the inner tube was patched. Up to this point, we had been traveling through a large rubber tree plantation. Votha said that the whole thing was owned by a Chinese/Khmer man. He ran the place in the old style where he owned not only the plantation, but the town and shops where the employees live.

 It was obvious that we were approaching Baesrak when we passed through fields that were absolutely full of the pits where hand mining had already occurred. The place looked something like a cross between a prairie dog town and the no-man’s-land between the trenches of WWI. Every square inch had been dug up!

 As we moved into town, we came across active pits in peoples’ yards. These pits were the same as before – a hole is dug straight down to about thirty feet to find a three to six foot gem bearing strata. The miners said that it takes about a day-and-a-half from starting a new hole until reaching the gem strata.

We walked through the town a bit and stopped to speak with some villagers. Apparently there was a big Korean mine nearby. They said that there had been a French videographer the previous year. Since coming home, I have tried to find if this video had been produced, but I cannot find anything.

 Both Votha and I heard a familiar sound while sitting there. We had been hearing a gasoline water pump in the distance. I followed Votha down the hill through the banana trees. On the opposite hill, we could see the unmistakable signs of a larger scale mining operation. This claim was being operated by two men and one boy. They were using the standard high pressure hose to wash away the soil and send it down a flume. This time, they captured some of the gem bearing soil on a plastic tarp to search through at a later time.

 Once we made it back to the motorcycles, we headed back through town to the Korean operation. On the way, I asked to stop at a building where some rough and cut stones were being traded. They showed us quite a few nice pieces. The owner had a very nice large zircon on his finder and a woman there had a necklace full of stones. We did not ask about the ring, but the woman said she would sell the necklace for $400. This seemed a bit high after visiting the gem dealer the previous night. I bought a single stone before we moved on.

Our arrival at the Korean mine was not welcomed. The guard there chased us off so I did not get any photos. However, we could see that they were using heavy equipment to excavate the soil and they had a trommel and shaker table to separate the gems from the tailings. This was by far the largest operation we saw.

We had considered visiting another site called Poom (Phum) Gop, but it was too far away and I needed a break from the rough motorcycle rides. Our day was far from over anyway since we still had to get back to burn the stones that we had collected.

The schedule that Votha had set was quite busy, so we did not even stop to shower before heading off to get our stones heat treated. I did not have enough stones to fill a crucible for the heating, so I bought 250 grams of small stones for $25 in order to fill up the crucible.

Cooking the stones would only take about two hours after starting the furnace. The first step was to put the stones in a small crucible without any flux. Then a lid was places on the crucible and then sealed with cement. This was placed on the stove to dry the cement and drive the air out of the crucible.

 Next, this crucible was placed inside a larger crucible and the lid was again cemented in place. While the cement dried, the furnace was loaded with charcoal. Apparently the real secret to heating the zircons lies in the type of charcoal used. The identity of the proper wood was never mentioned. The crucible was placed on top of the column of charcoal and then the furnace was lit with a gas torch.

The final step was to attach a chimney to the furnace so that the exhaust gases would not fill up the house. Heating rubies and sapphires requires a high temperature, and some sort of blower is used to generate a higher temperature. I did not see any type of blower around, so I guess that the charcoal just burned at a natural rate as the fire moved up the column of fuel.

 All that was left now was to wait a couple of hours. This time was spent in the shop talking to Mr. Kruy. I asked about the history of zircons in the area, but he was not sure about the history, He believed that the original people in the area known as the Kola had first discovered the stones. Most of the Kola people had been killed by Pol Pot and his regime during the civil war.

 The local zircon can be heated at a low temperature to cause the blue color. They could also be heated at a higher temperature for a longer time to get a yellow or orange. There are more zircon mines across the border in Vietnam, but they do not respond well to the heat treatment. These Vietnamese stones only acquire a very pale blue when heated. There is a constant risk for burners that unscrupulous dealers will sell the Vietnamese stones mixed in with local production.

Zircon production in the Bokheo area has been good for a couple of decades, but things are beginning to slow down. People believe that many of the good mining areas are now locked under the rubber plantations. The areas available to the small scale miner will be worked out in five years or so.

Official records show that licenses have been issued to two companies for mining zircon in Bohkeo District. Ultra Marine Kiri (Cambodia) Ltd. received a license in 2005 to mine in the Pating Thom village in the Ting Chak commune. The same year, Seoul Digem Cambodia Co. Ltd. received a license to mine in the Lomphat District of Ratanakiri.

Before long, the stones were ready. The crucible was brought out into the shop and the contents were dumped into a dish. The zircons had a very intense blue color while they were hot. This color became more subdued as they cooled. After they cooled completely, they had a color similar to fine aquamarine.

It appeared that Votha and I had seen the highlights of zircon mining in the area and I was too sore for another outing. We decided to leave Ratanakiri the next morning and head back to Phnom Penh. There was a mysterious new mining area in the very south of the country and my schedule would allow us to make it if we gave up on further trips around Ratanakiri. I had heard that there are sources of amethyst and peridot in the area, but I was not able to investigate this

 3. Takeo
A new source in the south

The trip to Takeo on Highway 2 from Phnom Penh only took us an hour or so. This was much better than our previous all day rides. We drove around the city, but did not see any promising places to stay or any gem shops. Votha thought that it would be best to ask some police officers he had seen at an intersection for information, so we turned around and headed out of town.

This was our lucky day! One of the men standing with the police officers had a relative who was a miner/dealer in the hills where we were heading. A quick phone call confirmed the village where we needed to go. He man on the phone said that there were no nice hotels, but a couple of guest houses were in town. The ride to Phnum Den would only take another thirty minutes.

Once in the village, we walked around to see what kind of stones were being found nearby. There was lots of quartz and topaz. Most of quartz was of the smoky type and the topaz was colorless. There were a few light blue cut stones and some rough. I thought that they looked more like tourmaline than topaz judging by the features on the rough stones. Votha had already formed a plan for the next day, so we spent the remainder of the afternoon at the same restaurant where we had lunch. It seemed to be the only decent place to eat in the whole place!

We were up and on the move before 7 AM. Actually, I don’t think I ever fell asleep because of the heat - the cinder block buildings just never really cool down at night. A quick breakfast of noodles is all that we needed before heading out.

Votha first attempted to find our way to the mountain on our own. This did not work so well, so he asked directions and found that we needed to head south to a tiny village on the west side of the road. We hired a local motorcycle driver to be our guide.

The road ended at the Churous Phaûk Waterfall. We climbed up past the waterfall into the mountain. It was not long before we came across a family digging in a small stream bed (10° 37.616N by 104° 51.468E). They had not found much so far that morning. There was another couple digging in the hill above this family. They too had not found anything of value.

 It was obvious this is a pegmatite deposit. So far, mining is only done by hand in the streambeds and weathered alluvium. Certainly more material is still en situ and would require hard rock mining techniques for recovery. There must be tremendous mineral specimens locked away in pockets of Phnum Bayang Kao.

Votha said that we could spend days hiking around the mountain looking for other miners, but the process would essentially be the same. All of the work was done by hand. This area had only been discovered about three years earlier when a visiting gem dealer on holiday noticed a stone in one of the streams. The mountain is very rugged, so using heavy equipment is not convenient.

By this time, some souvenir dealers had appeared in the parking below the waterfall. I bought a small quartz carving of a Buddha, a faceted smoky quartz, and some aquamarine. The stone that I had thought was blue tourmaline the previous day had turned out to be aquamarine. One of the women there said that another American had been there just a week before and bought more than $1000 worth of stones from here!

After our visit to the miners on the hillside and the waterfall, we decided to visit an ancient temple on the north end of the mountain. It is said that this temple, Phnom Bayang, predates Angkor Wat which means that it is over 1000 years old. There was a small community of Buddhist nuns living just below the temple. It seems that it is rarely visited by tourists. There was a very nice view of the hills to the south were the stones were being mined and the plains reaching out to the east into Vietnam.

Back in the market, I bought a nice smoky quartz crystal, and unknown green stone (later proved to be apatite), some rough topaz and possibly aquamarine and some unknown blue stones. The woman who I bought most of my stones from said that a Thai dealer had come through just recently and bought up all of the good aquamarine. This area does not produce a lot of stones, so it is easy to see how a single dealer can buy out everything in the town.

This small area seems to be the only spot in these mountains to be exploited for its gem potential. There are a few more small mountains in this area on both sides of the border. It seems likely though that Phnum Den will only produce a trickle of stones for now.