Aquamarine!

In a small-scale Cambodian gemstone mining site the predominate stones are quartz (rock and smoky) and topaz, but now we can add aquamarine to the menu of offerings.

Takeo Province, Cambodia, produces not just white and smoky topaz, but also aquamarine.

This week I spent a day at the base of the mountain talking to the gemstone cutters and sellers. And looking at their stones. Especially their gemstone rough (t'bong chau).

Most of these uncut crystals are very clear, though the larger they are, the more likely they are to be included. I looked at the inclusions with my 10X loupe and they exacty what was expected (GIA Gem Handbook).

All of the crystals in the photo above are Aquamarine, except for the fat stone near the center and on the top of the picture, that is Topaz, typical of what they find in the nearby stream beds. But the most telling point was that many of the uncut crystals are clearly symmetrical six-sided forms; Topaz simply does not grow that way, though some of the sellers persist in selling cut stones which are clearly too light in weight to be Topaz (by my admittedly subjective heft) , as Blue Topaz.

The fewer the inclusions, the smaller the piece of rough. The clearest stones -- and some of the crystals are flawless -- the thinner they are. There are two results: first, the thin small stones are cut into rectangular step-cuts (like an emerald, its 'cousin', might be) and second, the larger crystals with their large inclusions and breaks are carved into Khmer or Chinese Buddhas.

My whole plan to get two pieces of cut gemstone, one Topaz, the other a blue stone of the same carat weight foundered abruptly. (I wanted to see if the Topaz was smaller in volume).

The sellers do not own even the simplest of means to weigh their stones. They seem to estimate by eye the size of the stone and distinguish between them only on the basis of clarity, color if any, and type of stone, before they set their price. And my plan to buy some cut blue Aquamarine (and make tens of dollars)? That plan foundered also: any of stones available with significant color were visibly included. The brilliant, cut white (clear) Topaz is actually amazingly cheap; easy to see why it has been mistaken for diamonds. The sellers say that they are attracting a lot of visitors from Hanoi and from Ho Chi Minh City. They are well positioned to do that, the mountain is only half an hour from the border.

If you visit, remember: this is a culture that bargains. With the slightest pressure the sellers will drop 25% to 30% off of their marked price (just ask: "Som joh damlei bantic baan tee?" Can you please lower the price just a little?" And if that is a bit too much (my phonetization surely leaves much to be desired), just wave your hand, palm down, in a downward direction, pointing at the price, with a suitable modest and calm look on your face (Cambodians do not know how to react to anger or outrage or righteous indignation even if feigned (I don't know if they even do indignation, never seen it, or the signs are not accessible to foreigners :).

And at the end, say: "Awgun! (Thank you)" They will really appreciate the effort.

The fact is buying a gem from a poor Cambodian dealer is not just about getting a beautiful gemstone at a decent price, but also about walking away, thinking: what a nice lady, that was fun! :)

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Headed Up The Mountain

The miner's wife that I had met on my previous visit to the top of Takeo's Topaz Mountain walked up and talked to us during our most recent visit. I had come back to the mountain two weeks later to determine once and for all if the blue stones that her husband and relatives and neighbors were digging up was in fact Aquamarine or not. (It was :)

She is such a lovely woman. I asked what she was carrying and she let me look in the straw basket that hangs off the front of the stick across her shoulder. Cooked rice in a blue plastic bag. Four small fresh fish, and a cup of coffee with milk and ice carefully placed in a clear plastic cup, covered with a plastic cap, but with a straw already inserted. An empty capped plastic jug hung off the stick between her and the coffee. On the back five kilograms of uncooked rice

She had an hour climb ahead of her, but was remarkably cheerful about things.

Like I said, a lovely woman.

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Blue Topaz or Aquamarine?

Once I got back down to the bottom of the mountain (hill), I went back to the faceted gemstone seller and asked for a piece of Blue Topaz rough (I will call it this, in deference to her :). She sold me a light blue-green stone for five dollars.

I took it back to Phnom Penh with me and did some digging in my books. Along the right had side of this post are some views of this piece of crystal. I don't have the ability to measure its specific gravity or reflective index (that would put to rest the question easily), but I can list some arguments in favor and against it being Aquamarine based on what I learned or could see.

1) Aquamarine is not ruled out by its color, nor is Topaz. Both stones occur naturally in low saturated blue-green colored gems. On color it could be either.

2) Topaz and Aquamarine are known to occur in the same geologic setting, so there would be nothing surprising about Aquamarine being found in a location where mostly Topaz had been found until now. In fact Aquamarine is often found with Rock Crystal and with Smoky Quartz as Topaz is here. Nothing to rule out Aquamarine here.

3) The gem sellers all say that this light blue stone is more difficult to cut than is Quartz (there never was a question of whether this was quartz, quartz does not occur naturally in blue). They could not say if faceting the stone was more difficult or easier than for Topaz. The ones who believe that this stone is naturally occuring blue Topaz say that cutting is the same as cutting Topaz itself. If it were Aquamarine, it would be harder than Quartz, but possibly as hard as Topaz. Nothing determinative here. Easy to see why the cutters cannot tell. (Mohs is a 10-point scale and a standard gemological standard for measuring relative hardness. Diamond is 10.0.)

Quartz (Mohs=7.0); Aquamarine (7.5-8.0); Topaz (8.0)

4) To my mostly untrained eye, the crystal form of the stone appears to be hexagonal. If I am right, that might in and of itself rule out the orthorhombic Topaz.

5) The piece of crystal rough that I bought has striations parrallel to the long axis of the crystal. Both Aquamarine and Topaz are known to display that, though most of the Topaz crystal rough I saw at this site (and bought on a previous visit)  had been worn and pitted by their travel to a final alluvial deposit. On the other hand, and contradictorily, a lot of the quartz was so finely formed and unmarked that the gemstone dealers talked about how it looked as if it had been hand cut and polished!

So, until I can get the specific gravity of this stone measured (Aquamarine: 2.63 - 2.91, Topaz: 3.5 - 3.6, strangely different sources vary in the numbers they provide), or measure the refractive index on a cut stone, I may be out of moves.

Unless. Unless I go back and look at two cut stones, one clear and clearly Topaz, and the other light blue, same cut, same carat weight, and see if the Topaz is smaller (higher specific gravity).

Or. Or, ask for two stones that look to be the same physical size (volume) and see if the blue one has a lower carat weight.

Yeah. Yeah, I think that is what I will do. And if it appears to be Aquamarine, I will buy me a couple of stones. You should see the international retail prices for good color stones. :)

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At the Mine Head

In previous posts I have described Topaz Rough found in Takeo Province, faceted stone sellers at the base of the mountain where the stones are found, the climb up the mountain, and the view from the top. We also met an old miner who lives on the mountain, after meeting him we followed three miners to their work site, the mine shaft they have dug.

Well these mine 'shafts' are not that large. Once a promising location is found, a place thought likely to produce sellable stones, a group of men is organized and digging begins.

We went to one such location with three miners to see how the work went. It is very low tech, but that is a good thing. These rice farmers have a source of income that they otherwise would not. They are extracting at a pace that they can sustain.

Though no one knows when or if the mountain will play out (but good digs are more and more difficult to find and at greater and greater distances), but in the absence of major commercial interventions (which destroyed the Pailin ruby and sapphire mine sites, and made major in-roads among the zircon sites in Ratanakiri), these people are set to make money in small increments for many more years.

As they have for about ten years now.

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Home on the Mountain

Most topaz miners 'commute' to and from their villages below. But a few live on the moutain-top, where small fruit orchards and vegetable gardens have been planted.

Our guide took us to the house of one man, who claimed to be more than seventy-years old. There we visited with him, took a look at his tools and the stones that he had recovered but rejected, unsellable quartz and topaz. Some of the discarded stones looked like rose quartz, another co-occuring mineral to aquamarine!

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On Top of the Mountain

The mountain is really a three-fold series of climbs. Near the very top, the view is almost breath-taking (the climb sure is). The vast flood plain of the Mekong is in clear view.

A nearby mountain is home to an ancient (probably Chenla) temple/monument. ($10 will get you a guide to take you up. On a motorbike!)

The hill we are on is strewn with boulders. Somehow it, and many similar hills across the generally flat land of central and southern Cambodia survived millenia of repeated rainy seasons and seasonal flooding.

I learned later that aquamarine and topaz are called pegmatite gemstones and occur in geologically similar conditions, along with rock crystal and smoky quartz, they "are formed in the vicinity of crystallizing granite bodies from the hydothermal solutions released by them" (Note One).

Whether the boulders I was seeing were pegmatite granite, I do not know, but the geological correlations indicate that where there is quartz and topaz, there may often also be aquamarine. The identification offered at the base of the mountain now seems less and less unlikely!

Note One: Bonewitz, Ronald Louis. "Rock and Gem: The definitive guide to rocks, minerals, gems and fossils", DK Books, page 35.

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Up The Mountain

The base of the mountain is very pleasant. Cambodians would visit, as might some tourists, even if Topaz had not been discovered.

A fresh water stream tumbles down the mountain-side, slipping around and over the large boulders strewn across the landscape.

A small dam has created a swimming hole and children bicycle out every afternoon to cool off after school. An easy path leads up and away from the base of the mountain, across a small metal bridge.

Locals say that most of the miners come from four or five surrounding villages and they are organized into 'platoons' (my word, can be as great as fifty men) once someone has identified a likely sight in the heights above. Most do not stay on the mountain but gather in the early morning hours and walk up; they come back down before dark.

Finding a mining site requires a local guide. There are lots of paths on the mountain. Mining dig sites are farther and farther from the start point, and active sites are difficult to find. I paid a guide $10 to take me up. After climbing for an hour and a half, and going about 5 kilometers (guide's estimate, I am abysmally poor at estimating distance), I thought that the price was more than fair.

It turned out that he was a wedding photographer, had good suggestions for photos, and since he knew the miners, could sweet talk them into letting me take pictures!

(Though the government has taken little notice of their efforts for the ten years that they have been at it, they continually worry that some day it might. By Cambodian law all mountain tops are state property. "Out of sight, out of mind" is probably their watchword.)

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At the Base of the Mountain

A sandy, one-lane road leads from the national highway to the base of the mountain where faceted topaz is sold. A military-style checkpoint monitors a drop gate over this road a kilometer short of the mountain, but checking through there is quick, a simple formality, and nothing in the pleasant interchange reveals the purpose of the facility!

Cars can easily make the five-kilometer drive in, if the weather is dry, and motorbikes have very little problem except for the parts of the road where the white sand is at its thickest, back wheels can slough and spin, but if you are using a local driver, no worries. They are experts.

A dozen women have set up shop at the base of the mountain, there is plenty of parking and shade. Their display cases are glass and metal, but their 'stores' are bamboo, slim-cut timber with sugar palm foilage on the roofs. What you would see anywhere in rural Cambodia.

All of the stones are very clear, with limited inclusions, many are colorless, some with a hint of yellow (see the stones at the head of this blog). As you would expect with 'raw', untreated (but faceted), natural Topaz -- the stones are brilliant (in the past they have been mistaken for diamonds, see for example, the Portugese 'Braganza Diamond').

One should be aware of that the displays present topaz and quartz both of which come from the site. The smoky topaz and the smoky quartz may be difficult to differentiate, except that topaz 'feels' heavier (compare stones with similar volumes, the carat weights should differ), its specific gravity is 33% greater than that of quartz (approximately 3.5 versus 2.6). To me, topaz also has a kind soapy feel, quartz a glassy look and feel (but that is very unscientific).

If you are unsure of your own differentiations, you need not worry, I believe that these dealers are honest, They know the price they will all pay if word of mouth indicates that they are cheating customers. They are fully aware that the hardness of Topaz is greater than that of quartz, for them differentiation is easy, as they sub-contract the cutting. If the lady says that it is Topaz, you can take it to the bank.

There is a very wide range of cut stone sizes, with some very large ones available. But it in this case size is not necessarily better, hard to know what to do with a 50-carat cut topaz! And with prices between $5 and $10 per carat, total costs can mount quickly. And if you are used to cut citrine or amethyst, a five-carat topaz will seem somewhat small -- again its density is greater than quartz.

The lady in the picture above was the first one to show me what they all call blue topaz. The color of all the stones that I saw was blue-green, a sea-green, as the Khmer has it (poa duk samot - seawater color). The saturation of the color varies from stone to stone, but the most deeply colored are still very light.

When I was told that the stone was a natural blue topaz, my initial reaction was disbelief, disbelief out of my own ignorance. On returning to Phnom Penh I turned to the trusted Handbook of Gem Identification (Liddicoat, GIA), and yes, there are naturally occuring Topaz gemstones that are blue, but their commercial value is low since much more saturated colors are easily available from heat-treated and irradiated natural stones.

Back at the bottom of the mountain, another lady sitting with the seller I was speaking to, bashfully whispered 'aquamarine', which I did not know what to make of, since I knew little about the stone.

I aimed to learn more. Aquamarine would be interesting. If Topaz is more valuable than Quartz, though both are very common, good faceted Aquamarine is significantly more valuable than Topaz.

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Takeo Province - Cambodia's Topaz Mines

Takeo is the name for both the Cambodian Province and for its Provincial Capital. Takeo town: roomy, uncluttered, quiet and slow; it is about an hour's drive from the Vietnamese border.

The Province is located in the midst of the flat, rainy-season flooded Mekong Delata. As you can imagine, rice growing is very important to the local economy, and with all of the water, so is fresh-water fishing. A stay in Takeo would not be complete without sampling the fresh water shrimp, big and sweet, and unfortunately, increasingly expensive.

In the town itself there is little sign that topaz gemstones are an important part of the local economy. In a visible sense, they are not. Not the way that sapphires rubies once were in Pailin Province, or that Zircon still are in Ratanakiri Province. You walk up the main streets in both Provincial centers and you see lots of shops But in Takeo there are middlemen and women who have shops in town, shops for both the cut stone and for topaz gem rough. And at the base of the mountain where the mines lie, near the Vietnamese border, an informal set of shops have set up business.

I had visited the town about two years ago with a good friend of mine who (with his wife and children) run a jewelry counter at Psaa Toul Tompoong (Russian Market) in Phnom Penh. The stones that I saw then were beautiful. A lot of clear, clean, colorless Topaz was being found and cut on the mountain and sold at its base; if you wanted rough, you could buy that in town, but you had to know where to go, as my friend did.

What brought be to town this time was the rumor that light-shaded blue topaz was being sold. Though I have studied gemstones (colored stones mainly) at GIA Bangkok and at AIGS, I thought that the color of blue topaz was only a product of heat treatment and irradiation (as the deep blues that we typically see in jewelry shops are); I thought in short that there are no natural blues. It turns out that there are naturally blue stones found at mine sites (very light colored ones), but the blue stones found in Takeo are something entirely different as this series of blogs will reveal!

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Topaz Rough From Cambodia

Tako Province is south-east of Phnom Penh, not even one hundred miles. National Highway Two runs to the Vietnamese border-crossing south of Takeo Provincial Town at Phnom Denh. If you look at a satellite map of Takeo Province you can see where Route 2 crosses into Vietnam. Just before the crossing is a mountain west of the road reduced dramatically by quarried dirt, stone and clay 'stolen' for road projects; that is Denh Mountain. Just north of that is another mountain, same side of the road no name on the map, but home to Tonleab Village. Its interior is relatively unmarked by tree cutting or cropping. It is on this mountain that Topaz was discovered about ten years ago. Digging sites are a five kilometer climb into the interior of the mountain: an hour to an hour-and-a-half! Gem sellers sell cut gems at the base where the dirt road from town (Kampong Chrey) leads to a very nice recreational area with mountain streams, swimming hole -- with a moutain backdrop.

Above is a picture of four pieces of Topaz rough. The crystals are pitted from their journey to their final resting place, the mostly clay soil of the mountain. But Topaz is quite hard, measures at 8.0 on the Mohs scale, softer than Rubies or Sapphire (9.0) and diamond (10.0).

It is also one of those gemstones, like amethyst and citrine, or zircon, which are often found in large pieces without major inclusions. The crystal forms in Orthorhombic system. Geologists call its crystal habit 'prismatic'. The vast majority of the stones that are cut for sale are clear or have a light yellow or brown tint. There are stones being dug from the top of this mountain that are very light blue but the gem sellers at the base of the mountain are not certain whether it is blue topaz which they have cut and are selling. One lady whispered aquamarine to me. (We will pursue this question in another post :).

The stone above was photographed in early morning light, even though it is pitted it is translucent enough to glow with the rising sunlight that backit it.

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Blog Aim. Let's Go On A Trip!

I have been fascinated by Cambodia's gemstones since the late 1990's. Rubies, sapphires in blues and greens and yellows, brilliant zircon in white, yellow, orange and blue. Spinel and garnets too. Brilliant clear and smoky topaz has more recently been found as the ruby and sapphire mines of Pailin, like their Thai neighbors, across the border has played out. Lots of amethyst and citrine; smoky and rocky quartz too.

Cambodia is no Sri Lanka whose magnificent and varied mines are matched only by Madagascar (which makes sense since they were once conjoined twins, torn apart by drifting tectonic plates). But it is rich in possibilities, little of it is commercially mined, so visiting mine sites is a different way to get close to the Cambodian people, of connecting with them in their varied contexts as they struggle to make a living and raise their children, while you dig into one of nature's wonders.

Gemstones! Gemstones are a gift, no matter how common. The deep purples that amethysts naturally take on, the stunning deep peacock blues that heated zircon sometimes show. And how about the wonderful grass green of peridot, the hardness and flash of a well cut topaz? They are just so much fun. And there are surprises also as I hope a series of posts on this blog will show.

We will start our tour of Cambodia's gem mines with a visit to Takeo Province and the Topaz mines there near the mountain, Phnom Den. Thanks for coming along!

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