A zircon miner examines a stone sluiced from the mud.
Its blue can be as attractive and deeply saturated as a top quality sapphire and
its brilliance rivals that of a diamond. Cambodia's zircon deserves more respect
than it gets in world jewelry markets - the problem is that it is not well-known.
One problem is a lack of name recognition, or even misrecognition'. Many people hear
zircon and think zirconium, or cubic zirconium, a diamond simulant, a lab-grown,
synthetic gem, the stuff of late night home shopping networks.
Few people are aware that zircon is a natural gem and that it comes in colors that
vary from colorless to yellow-orange, and gold to a variety of blue hues - near pastel
to deeply saturated.
Almost all stones sold are flawless to the eye and to a 10X loupe (or should be).
But that is a problem too, since most of us know that if a stone is "too perfect"
it is probably not real.
Zircon's natural dispersion may also work against it. It can be nearly as brilliant
as a diamond, and if you have never seen a good zircon before, its deep-saturated
blue color and diamond-like flashing highlights might lead you to conclude it must
be fake. But they are real; stunning, flawless stones are being mined, treated and
cut in Cambodia every day.
Baw Gaew district is the oldest and most famous source of zircon in Ratanakkiri,
the only province where the stone is mined. Many Cambodians don't recognize the name
zircon, but it is widely known as t'bong baw gaew after the best-known source, or
t'bong khieu Ratanakkiri (blue Ratanakkiri gems).
In the last three years mining efforts have shifted to an area in the province called
Jomrum Bai Srok, which residents say was a refugee collection point and camp in the
All digging in Ratanakkiri is done by hand, with narrow shafts sunk into the ground
in gem-producing areas in search of layers of gem-bearing soil. Miners in one part
of Bai Srok dig to 15 meters and generally encounter gem soil at between ten and
13 meters. The stones are not embedded in rock, but lie scattered in loose, crumbly,
clay soil from which they are easily separated.
Hundreds of shafts have been sunk in and around Baw Gaew. The small town has grown
so much that temporary structures have been built over older working holes. Some
residents even mine underneath their houses.
Outside town a large, low hill is covered with holes, more of which are abandoned
than worked. The newest holes are clean of all vegetation, but abandoned holes can
be overgrown, so care is needed when on site.
Each working hole has a small windlass that allows a bucket to be dropped into the
hole. Miners climb down into the mine using hand and footholds cut into opposite
sides of the shaft.
Once a gem-bearing layer is found, it is scraped out. Then the bottom of the shaft
is expanded sideways, sometimes with dangerous results. Other shafts can be sunk
in line with the located gem-bearing vein in order to tap into it from a different
It is easy to spot the holes that are successful. If none or only a few stones are
found but the miners are still hopeful, the dirt is sorted out by hand by mud-slimed
miners sitting on the ground.
Successful shafts generate enough money to pay for water to pan the dirt. Miners
stand in small reservoirs lined with large plastic sheets and slowly sort out the
stones by swirling the soil in flat, tightly-woven baskets.
Miners say only 20 percent of the stones that they find are salable. No one would
say how much the rough stones sell for, but the on-site buyers are easy to pick out.
They are all clean, smartly dressed young men who carry small, powerful lights to
"candle" the stones.
Large stones can be rejected if they have too many cracks inside. A cut stone with
eye-visible breaks, fractures or inclusions has little value because almost perfectly
clear stones are quite plentiful.
In Ban Lung rough zircon is sold by the kilogram (5,000 carats) for $2-3,000 depending
on the average size of the stones. The customers are mainly Thai buyers who take
them back to Chantaburi to be treated, cut and sold at the famous gem markets.
Ironically in the recent past the most common name for zircon among jewelry buyers
in Phnom Penh was t'bong Thai (Thai gems).
Siew Chheng, a jewelry seller at the Russian Market, says the demand for zircon among
foreigners has increased over the past year.
Gem cutters in Ban Lung say that the largest cut gem they know of was about 40 carats.
A top quality stone of that size would cost about $50 per carat in Ban Lung (more
in Phnom Penh). Prices for top quality zircon can vary from $10 to $30 dollars a
carat, depending on the size of the stone.
I met a Tampuan miner who lived in one of four villages with small scale mining operations.
He had a 100 carat rough stone that he wanted to sell for 2.5 million riel (about
$640). Since he saw me as a potential buyer, that is likely to be substantially higher
than a negotiated price.
Ban Lung gem dealer Map says he uses five separate quality categories for cut blue
stones and three for yellow. Prices vary according to total carat weight and color
saturation, which comes from heat treatment.
Up from the depths of the earth, a miner squints against the light.
The heating process is only well enough understood and well enough controlled so
that statistical results can be achieved. You cannot predict what will happen to
a stone, but if it is done well, the change should be permanent.
Twenty percent of heated stones will turn yellow or white, while the rest will become
the more valuable blue. Only a small fraction of those will achieve the most valuable
highly saturated color.
Even if the 100 carat stone turns a deeply saturated, permanent, and therefore valuable
blue, one can expect to lose up to 60 percent of the rough weight when it is cut.
Finally, there is always the possibility that cutting will reveal breaks which were
not previously visible. That again reduces the size of the final stone or forces
the cutter to fashion several smaller stones rather than a large one.
The greater the number of stones cut, the more of the original weight will be lost.
And the smaller the average weight of the stones, the lower the per carat price.
There are artificial zircon stones around, but if you buy from any of several jewelers
with established reputations for integrity in Phnom Penh, you will have a stone you
will enjoy for many years to come.
Traveling to Baw Gaew
Reaching Baw Gaew from Ban Lung town is never easy, and worse still in the wet season.
One way is to get a Chinese-style jeep, four of which wait in front of the town's
taxi stand at the main market and leave when full.
Motorcycle taxis are also available for 10,000 riel one way, but they use paths rather
than the main road for two-thirds of the journey. The route is more scenic, but the
last ten kilometers takes you down slippery hills and jungle.
There is simple accommodation and safe food and water available at the mining town.
Reaching there on your own is not recommended.
John C. Brown has studied gem identification and grading at the Gemological Institute
of America. He visited Ban Lung and Bai Srok July 13 - 19.