GEMMOLOGY CANADA Special Issue
by Donald G. Coughlin
View/Download this article 1 MB, Acrobat Reader or plug-in needed (right-click for direct View/Download to your computer)
Return to Top
It is hard to imagine a more fascinating and interesting country for a gemstone enthusiast to visit. Whether the visitor is a lapidarist, gemmologist,jeweller, or hobbyist -- Sri Lanka has all one can ask for. This is a photographer's paradise! (Editor: View some interesting pictures at GEM MINING IN SRI LANKA - An exciting trip to the gem mines of Elahera, Sri Lanka.)
Sri Lanka, still fondly called Ceylon by many inhabitants, is an island lying off the southern tip of India. Filled with colour, excitement, friendliness,folk lore, and superstition, Sri Lanka is the "Pearl of Southeast Asia." Languages are primarily Tamil and Sinhala; however, English is often spoken and understood in all major tourist areas. In gemstone mining areas the "man on the street" knows little English, however, they try hard and you should be patient when they misunderstand you. Various reports claim much of the country's surface has gemstone minerals beneath it. Easy to believe, because there is no apparent sign of gem shortages despite centuries of mining.Very little in Sri Lanka compares with the Western world, and that includes customs and traditions that are often directly related to Astrology. Every lunar month there is "Poya" day, a national Buddhist holiday, and most businesses are closed. Taxis are plentiful and inexpensive, the commonest being the non metered three-wheeler scooter van called "Bajaj" (brand name) or simply "three wheeler." The Bajaj is fun, but many passengers find it expedient to close their eyes -- when cows cross the road for example. Ditto, when a speeding private bus make it clear there is no room for your little vehicle on the road. It is normally quite safe, and your driver will slow down on your insistence. Prices are not much lower than regular metered taxis, and MUST be negotiated before embarkation. Just ask anyone in the vicinity for help, and they will haggle for you! I would strongly recommend you read a guidebook to learn about climate, customs,tourism, etc.
WHERE, AND HOW TO SHOP
Return to Top
There are thousands of gemstone shops sprinkled throughout Sri Lanka. Some are elegant (luxury hotels and museums), while others may be small and unassuming. Normally one's purse dictates which sort of shop to deal with.Generally, gem dealers are courteous, friendly, helpful, and rarely get offended when a customer walks out without buying. Apart from the shops, and with a great deal more fun (and often much frustration) are the street gemstone hawkers of Ratnapura and other mining towns. It is impossible to pull out all your testing equipment at these street markets. Your best bet is to become expert with a 10x lens, Chelsea colour filter, "heft," and if possible --"Visual Gemmology" (or V.G. for short).
Okay, you arrive at Ratnapura ("Ratna" means gems, "pura" means area) so now what? There are many things the visitor should be aware of before stepping into the unknown, and the following information will help you:
WHAT INSTRUMENTS DO I NEED?
Return to Top When visiting a "Pola" (a street auction where all the action is), you will want to carry minimum gem-testing instruments. The following items may seem intimidating, but all are small and will rest easily in one's pocket or handbag.
* 10x lens
* small diffraction-grating spectroscope.
* small pocket size mirror: Though textbooks recommend a black non reflective surface for spectroscope testing, I like the unorthodox method of using a small mirror as a "table" for stones to be tested. This is particularly suitable for rough, and darkly coloured stones. Hold the flashlight on an angle and aim directly at the base, behind the stone. The whole stone will be illuminated by reflected and transmitted light, and often some absorption lines may be seen which were not visible using the orthodox method.
Return to Top If you use a prism spectroscope with non-illuminated wavelength scale, move the light around in several directions until it shows both the spectrum and scale. Please note that it is not a magic mirror! Often you would require the correct, standard method (minimal ambient light, a strong light source, and a matte black surface). Outdoors, I always use the mirror first, then if necessary resort to the more orthodox method. It is a matter of personal choice.
* sewing-machine oil in a small dispenser: Ideal to check rough stones for asterism or chatoyancy. More on this subject follows later under the "For the lapidary" section.
* Chelsea filter: This can be very useful out in the field. For example, a man is offering a large pale blue "aquamarine" at a reasonable cost. A quick look through the filter will not confirm it is aquamarine, but leans in favour of it should the stone appear strong green. If red, it is probably synthetic spinel; or if a dull yellowish colour it is probably topaz.Though the filter does not provide conclusive identification of stones, it can often show what a stone could (or could not) be. At the very least, it can arouse the suspicions sufficiently to refuse a purchase!
* 49 mm polarizing lens (PL): The primary use of the PL is to check rough stones for double refraction and/or pleochroism. This lens is often marked "PL" on the wider rim, and is obtainable from any photographic shop. It is a crude, but often quite effective, substitute for a polariscope. The PL is highly portable, easily cleaned, and inexpensive. TEST IT BEFORE BUYING!
If you have a portable polariscope so much the better.
NB: You will notice that the PL consists of two independent rings. The ring with the milled edge is the polarizer while the wider one is simply the accessory ring for attaching the PL to a camera. Lapidarists will find this method helpful for finding the optic axis of rough stones, and pleochroism. How to use: Shine your penlight on the stones at an angle, about an inch or two above the stones. With your free hand, grip the adaptor ring with thumb and index finger. Rotate the milled polarizing ring with your middle finger 45 degrees at a time. If this proves impractical (e.g. small fingers) then just rotate the complete PL back and forth. Hold the PL close to the eye, and you can observe the doubly refractive stones (faceted or rough) alternating from light to dark with every turn. Also one can detect dichroism, particularly with specimens of andalusite, good purple coloured Iolite, or brown topaz.
Return to Top View singly refractive stones in different directions, since you may be observing the direction of single refraction (optic axis) in a doubly refractive stone. Also, if your stone is on a reflective surface, you will be observing the polarization of that surface reflected through the stone! If stone remains inert, you can conclude it is singly refractive.
Return to Top Recently I visited my Lapidary friend, and he asked me to look at his spinel parcel containing about 25 rough stones. With one sweep of the polarizer I plucked out a bluish-white fractured and water-worn crystal. I could not positively identify this stone, but did confirm it was doubly refractive, therefore not Spinel. We then polished a facet and at home I identified it as sapphire.
* additional small penlight for visual gemmology: The small key-chain variety is excellent for its portability, and do not forget to carry spare batteries. Puncture, or cut, a very small hole in the centre of a small piece of black tape. Stick this tape over the penlight head.
* pocket size calculator
BASIC RULES FOR SHOPPING
Return to Top
* KEEP YOUR SENSE OF humour: This is most important and therefore heads the list. Sri Lankans enjoy a good laugh, and often local men laugh at you for no apparent reason. You should not take offence, and understand that they have a completely different mentality to yours and they do NOT mean to offend you! Whether laughing with you, or at you, try to take it in a good natured way. You should join in the fun even if it means laughing at yourself.
The same thing works in reverse, you can laugh at them for whatever the reason, and they enjoy the joke! Depending on how you view it, this sort of laughter can be quite refreshing when compared with our often exaggerated western sensitivities.
* GUARD YOUR MONEY! Do not flash your money around. Carry only small bills and plenty of small change, and only the amount you intend to spend.
* KEEP CALM! Do not let yourself "lose your cool!" These peddlers hound you to death, about fifty of them pressing in on all sides, and you must remain calm. Agitation only makes things worse, and there is a strong likelihood that poor judgement will result on your part. Just make it clear to them that they must "back off" or you will no longer discuss gemstones with them. Eventually they get the hint.
* KNOW WHAT YOU WANT! Decide in advance whether you will purchase cut stones, or rough. It is illegal to export rough stones from Sri Lanka. However, this should not prevent you buying some (particularly if you are a lapidarist and know a good stone when you see one). You can then take it to any established shop dealer who will be pleased to cut it for you at a low cost.
Cutting time, depending on the stone, would take only one to two hours (even hour is possible if you are in a rush). The average cost of cutting depends largely on the quality of the rough, and sad to say -- the colour of your skin. White people ("Suddha") normally pay considerably more (not just in the gemstone business, but for everything from visiting the zoo to parking your car!) Do not be too upset about these "surcharges" for it is usually a reasonable and small amount (I hate it on principle, but have to lump it.) Cutting a Sapphire may cost only $3.00 per carat, depending upon your bargaining ability -- and perhaps more important, your social behaviour. A smile can spark instant friendship in Sri Lanka.
* BARGAIN! Always bargain, even if a shopkeeper insists he has fixed, or "unbeatable" prices. I have yet to see a dealer let me walk out of his shop without reconsidering his "fixed" rules. IMPORTANT: Many dealers in Sri Lanka, whether in first-class hotels or gemstone shops, have as much as 30% mark up on their gemstones. Up to 20% of that is for the touring guide or agent, while 10% may be tacked on for discount purposes. (Foreigners often receive advice to refuse any purchase not accompanied by a discount.) So, if you are unaccompanied, then you should deduct 30% and even more to set a bargaining plateau,
* BUYER BEWARE! When you have agreed upon a price, you cannot, ever, change your mind! To change your mind after you have made a fixed offer is unethical, and not "playing the game." If this happens, (and it did to me), you will find many stern and angry faces closing in -- quite frightening to the uninitiated! Don't worry, they will never hurt you and are "teaching you a lesson," but your popularity rating has dropped considerably.
* AGREEING ON A PRICE: The hawker is offering his blue sapphire (cut or rough) for the bargain price of 12,000 rupees. (Note one dollar USA equals about 40 rupees, or pounds sterling 0.92) You like the stone, so you may feel you should start your bargaining at 4,000. Watch it! You will feel ill should the dealer immediately accept that figure! The streetwise shoppers (mostly lapidarists) offer, ". . . under 4,000." This leaves the door open, and if the seller agrees, then you start working on a lower figure.
* THE SINHALESE WAY OF INDICATING "YES": Many foreigners are confused when the seller shakes his head in a curious wobbling manner, much like we indicate "no" in Western countries. This delightful and unusual mannerism means "yes" in Sri Lanka. When I first experienced this peculiarity, I raised the price under the assumption I had made too low an offer! The laughter among the hawkers was a sure sign that I was not the first to make this mistake.
* SYNTHETICS, AND IMITATIONS: If the price seems "too low" for such a "high quality" stone -- it is likely the stone is synthetic! Test it if you have the necessary instruments -- or refuse it. Synthetics abound, thanks to dishonest people importing them from Singapore, Bangkok, et al. (NB: I buy them for study purposes but only for the price of cutting.) -Sapphire: Imagine your face when that beautiful blue sapphire "bargain," which you purchased under the glaring sunlight, turns a fascinating ruby-red colour under the artificial light of your hotel room! You just bought a synthetic "alexandrite" sapphire worth little more than the cutting price. You could have spotted this if you used your little penlight in the first place. Outdoors, you could simply cup the "blue" stone in your hand to reduce daylight; shine the penlight on the stone, and presto . . . the stone is red!
Synthetic star sapphire with too strong a blue colour, and "too perfect" asterism.
Synthetic spinel often imitating Aquamarine and blue topaz.
Zircon cat's eye being peddled as chrysoberyl cat's eye.
Brown zircons being peddled as sinhalite.
Because of greed and excitement, one can become incredibly stupid. For example, you think you have spotted a rare stone and in haste to "get away and admire the steal," you throw common sense to the wind. Sad to say, you forget to check the stone, and sadder still, you may even forget to bargain. I know from experience!
* BEAR IN MIND: More often than not, local gemstone dealers (as in most other countries) know little about gemmology! This is a great advantage to the intrepid buyer trained in identification techniques. It is shocking to see how many honest dealers unknowingly peddle synthetic stones. They are hurt and angry at having been duped -- and all apologize profusely when you point out their errors. What happened to them is unfortunate -- some crooked customer has pulled a switch, leaving the dealer with a dud!
Return to Top A dealer situated in a 5-star hotel, claimed he had two certified rare stones, (ekanite and taaffeite) for sale. I checked and found the certificates did not match the stones in question -- even the colours were wrong! I brought my portable refractometer and showed him that he had a diopside and a normal blue spinel. He was the victim of a "switch" deal.
* RARE STONES: The above is to your advantage for obvious reasons. You can make an excellent purchase, e.g., a beautiful spessartine garnet as a hessonite for only a couple of dollars, or a very rare taaffeite represented as a blue spinel for a similar amount. (Testing of rare stones is covered in the next part.) When you spot a rare stone, and obviously the seller is not aware of it, buy it! Do not let your conscience bother you too much in this grey area -dealers are "businessmen," and it is obvious that their consciences are at rest when they grossly inflate their prices on the unaware tourist.
* NERVOUS? If you are the nervous type, perhaps timid, or have very little knowledge of gemstones, then stick to the older, well established gemstone shops in downtown Colombo. These dealers are reasonable, honest, and value you as a potential "regular" customer. Certainly if anyone intends to invest a great deal of money, these are the shops to deal with.
In any event, I highly recommend you visit a gemstone street auction (Pola) and make a purchase no matter how small. For those trained in gemmology, this is a splendid opportunity to test your knowledge where it counts. The pleasure and enjoyment of perhaps being lucky enough to make a terrific purchase far outweighs the displeasure when one is ripped off. Being ripped off is a sure and positive way to learn, and is nothing to be ashamed of. On the lighter side, you will have something to talk about for the rest of your life!
* THINGS ARE NOT ALWAYS WHAT THEY APPEAR TO BE: For example, local descriptions of gemstones differ from text books!
A "Tourmaline Parcel" is a stone-paper filled with a mixed variety of stones with few (if any) tourmaline in it. Many peddlers call coloured stones "tourmaline" and the inexperienced buyer often believes these are all different shades of that variety. Normally these parcels consist of green metamict zircon, almandine and hessonite garnets, spinel, diopside, quartz varieties, and glasses. However on occasion a sharp eye will spot the odd chrysoberyl and rare stones such as sinhalite, kornerupine, and if extra alert -- taaffeite, ekanite, etc.
Quartz varieties (smoky, citrine, and rock crystal) are called TOPAZ (in English). The dealers are not intentionally misleading you (though such a possibility exists), but to them quartz is English for topaz! I wanted to purchase a faceted 1000 carat "topaz" at a five-star hotel, but instantly knew by the simple expedient of running my thumb across the table facet that it was a smokey quartz. Practice it! Topaz is very slippery and your thumb slides across the table facet as if it were ice while on quartz the thumb "sticks".
* PLAY THE GAME: It is wise to bear in mind that while many local dealers have little knowledge of gemmology, they ARE experts in their field, e.g., using their extensive experience in judging a stone by its colour and "heft," and in bargaining techniques. So, you have to beat them at their game by becoming the aggressor, pitting your knowledge against their experience. In such a showdown, knowledge should win every time.
* HAVE YOUR STONE CERTIFIED: If a gemstone is expensive and you doubt its authenticity, insist that you want the stone certified by the State Gem Corporation of Sri Lanka (free of charge without certificate, minimal charge with one), or other qualified agency, before you make full payment. The street hawkers usually work for a mine or shop owner, so are probably paid on a commission basis. Some may be pit workers who manage to "find" sapphires and rubies while out jogging, or perhaps the stones "...fell off a truck".
So, insist that your man takes you to his "Master", or brings him to you, and request the necessary certification. This applies to shop dealers and street hawkers alike - but only for expensive stones. The dealer will deliver both stone and certificate to your hotel room if he is sincere. Should the stone turn out to be synthetic, you may not see the dealer again unless he has an alternative stone of equal value on hand. (I understand the Gem Corporation will destroy the synthetic -- much to the dealer's dismay.)
* PURCHASING SYNTHETICS/IMITATIONS: Should you wish to purchase synthetics or imitations (natural glass) for study purposes or for collections, then when you spot a desirable specimen you can offer possibly rupees 50-100 ($1.50-$3.00) per carat. "Pit glasses" are attractive and worth collecting. You should practice the art of "heft" if you do not carry carat scales with you. It is very rare that a stone weighs what it is advertised to be!
* AMATEURS -- LOOK PROFESSIONAL: Have a bit of fun! Even if you are not a professional, you can appear to be one and hence get a better deal. Here are a few tips:
(i) Hold and use the 10x lens properly, close to your eye. Many dealers can spot the amateur instantly by improper holding. You can turn the table around by asking the dealer to look at inclusions in a stone -- and see how HE holds the loupe! Many dealers hold it incorrectly, about 1-2 feet from the eye, just above the stone.
Return to Top I asked one dealer to look at the bubbles in a blue Sapphire through my 30x lens, and he held it arms length, until it almost touched the stone! What made it more comical was the way he sagely nodded his head. Obviously, in using this "distant vision method" with such a strong lens, he could only identify a scratch on the stone's surface.
(ii) Examine stones as if you know what you are looking for even if you do not have a clue about gemstones. Also, seriously study the cut -- a poor cut (most stones are in this category) is a bargaining chip and you need not be professional to spot it.
(iii) If you have determined that the dealer has some knowledge of gemmology, you could throw a few heavy words around, such as isotropic, birefringence, anomalous double refraction, etc. He may be impressed and hence give you a reasonable price.
Return to Top Sometimes it pays to be honest. In a classy high class hotel, I chatted with the owner of a gem shop, and I pointed out that his prices were far too high even for such beautiful stones. Then I noticed (thanks to V.G.) that he had a beautiful spessartine rather than hessonite garnet as advertised. My first instinct was to buy it, however as he was quite a decent sort of chap I pointed it out to him. He admitted he knew nothing of gemmology, and became much more serious, finally offering me 40% discount on any item in the shop!
* LEARN A FEW WORDS OF SINHALESE: At least learn the words for stones you are interested in purchasing. The following is a glossary of the main gemstones/crystals with their names in Sinhalese (phonetically) as the locals speak. What follows is not an official translated list, but was volunteered to me by my lapidarist friend as words the street dealers use. You can appear knowledgeable by memorizing needed words, or read it off from the list -- it does not really matter.
Return to Top The street hawkers have no knowledge of gemstone identification, so purchasing stones can be quite confusing to the visitor. (e.g. Corundum is "sapphire", and ruby is ruby in English but "red sapphire" in Sinhalese. Also, though descriptions such as "precious" or "semiprecious" are frowned upon by gemmologists, these are terms very much in use in rural Sri Lanka.
Gemstone Street Sale - pola
Sapphire lot (small) - dalam
Semiprecious lot - thora lot
Blue - nilkata
Red (Ruby) - rathu kata
Pink - padmaraghe
Orange - padmaraja/rathnapushparaghe (whew!)
Yellow - pushparagha
White - suddhu nil
Garnet - rabaha
Hessonite - ratnagomeda
Almandine - kahata rabaha
Topaz - padiyam
Quartz - palingu (topaz in English!)
Citrine - kaha palingu
Smoky - kahata palingu
Amethyst - ambathest
Rutilated - kedimaya paligu
Aquamarine - patchepadiam
Spinel - kirinchi
Tourmaline - thoramalli
Zircon - jargoon (or thora)
Chrysoberyl - kanaka
Cat's eye - wairodi
Star stone - arunul
"Precious" - pajathi
"Semi-precious" - spatika
Natural crystals - yakakapu gal (literally, "devil-cut gem")
* CUTTING: Pay close attention to the cut of a stone. Sri Lankans has excellent lapidarists -- but unfortunately many intentionally turn out poorly cut stones, (e.g., 80% pavilion on sapphire is common) to gain maximum weight and/or colour. Just as shocking is an aquamarine with a good emerald cut crown, and a mixed-cut (very mixed!) pavilion to preserve weight and colour. Star sapphire/ruby and cat's eye: The crown is usually cut with excellent asterism/chatoyancy. However, the base is often left rough (to add weight) and as a result is very uneven -- one side measurable in millimetres and the other in centimetres.
* SHOULD I DISREGARD BADLY CUT STONES? No! Bargain hard because of the poor cut, and have it re-cut if the stone has enough body. Take into account the number of carats you may lose and of course the cost per carat. You can double or triple the value of most stones by re-cutting, so never turn down a stone simply because of the cut. Consider the "five C's" (colour, cut, carat- weight, clarity, and cost) -- disregard "cut" and check out the remaining four C's. If stone meets these, then it could be an excellent purchase.
Part II: BUYING GEMSTONES AND JEWELLERY
Return to Top
Sri Lanka is an excellent place to purchase lapidary equipment. Grinding and polishing laps are inexpensive and good quality. My custom built metal table with installed saw and lapidary machine, fluorescent lamp, laps and faceter cost less than US $1500. The cutting unit has a sensitive, adjustable platform on which you rest your faceter as you facet your stone.
Would-be lapidarists: Should you be contemplating a two-week holiday in Sri Lanka, then why not take a lapidary course here? A course, with a top- notch instructor, may cost $150. If attending full time you could complete the course in one week, learning all the major cuts (and you keep the stones you cut!) An added bonus is that you make many friends, and learn practical tips that text books never tell you.
For example, an interesting local practice of lapidarists purchasing rough stones in Sri Lanka, is the way they test rough corundum or chrysoberyl stones for asterism/chatoyancy. They put their tongue to the stone, or spit on it, to bring out the silky sheen (not a very sanitary method!). The better method involves wiping the stone against the forehead where the oily film included in perspiration produces excellent results. Often lapidarists carry a little container of oil (sewing-machine type is ideal).
Anyone wishing to purchase good natural crystals either for studying crystallography, or simply to add to their collection, should ask for "yakakapu gal" which translates "devil-cut gem". Many people believe that these crystals are cut by the devil because of their perfect form, and they will rush home to bring you their collections. You may be requested to accompany the seller to his home for viewing or you can ask him to fetch them while you await his return.
It is normally quite safe to visit his home, and you have the added bonus of experiencing the true local flavour. Women, for peace of mind, may prefer to accompany him if in a group.
These crystals are not normally gem quality, however they often have near-perfect crystal form (particularly spinel, tourmaline, zircon, corundum, topaz). Prices are very reasonable, but you must always remember NOT to make a precise offer as stated previously. He has got you alone, on his turf, and you must be that much more firm in establishing a plateau to bargain under.
Another excellent and reasonable course to take while on an extended visit to Sri Lanka is Gemmology. A full or part-time course in "Gemstone Identification and Evaluation" given by a qualified gemmologist costs only Rupees 5,000-6,000 ($125-150), and this includes use of all standard gemmological testing instruments.
Return to Top
Sri Lanka must be one of the most exciting countries in the world for gemstone enthusiasts, and the above is only an enticing morsel of the great "Gemstone Experience". Apart from gems, Sri Lankan tourism is priceless and must be taken advantage of. The sights, natural beauty, etc. are unparalleled (and I have 38 years of travel behind me for comparison!)
HELPFUL HINTS FOR SHOPPING AT A "POLA":
Return to Top
1. Always carry minimal equipment and money as mentioned above, or at least let nothing show! (Note: I was pick-pocketed.)
2. Choose a spot to examine stones where your back is to a wall of a shop, or even a motor vehicle. Then, you only have to watch fifty percent of the sellers, and your patience runs that much longer!
3. If you are unable to bear the excessive heat, and unable to tolerate the pressure of dealing with a swarm of people at one time, why not remain in your (air conditioned) vehicle? If you are on a bus tour, ask the bus driver to let you remain in the bus. Open a window, and accept one dealer at a time. He will hand you his wares to study and remain outside while you consider. This is my own method, and it works.
4. You can easily strike up a friendship with one of the dealers, and have him help you. He will be honoured at being selected, and will do everything possible to assist in every way. The natural conclusion would be a small reward when you finish with him.
5. For ladies: When outside Colombo it would be prudent to pay attention to your mode of dress. You will be in predominantly male surroundings, hence you will be encircled by many grinning men should you be wearing shorts or miniskirts. Sri Lanka is a male-oriented society, like it or not. However, should you like attracting this sort of attention then dress as you wish and rest assured you will not be ignored! In Colombo, they are accustomed to foreign tourists and it is unlikely you will "feel the pinch".
6. Playing "Pretend": When you see a stone you want, pretend you are not interested. He will pretend he will not take it back, but you hand it back while making a ridiculously low offer. He will laugh at your offer (while his cohorts share the joke) and that is when you turn to someone else. Now, he knows by the fact you made an offer that you are interested, and that his price must be lowered. When you prepare to leave, so does his sense of humour. He will panic and ask you to make a higher offer, which you can either do or stand firm. As you actually leave, he will probably accept your offer!
7. ROUGH SAPPHIRE ENHANCEMENT - BUYERS BEWARE!
Rough water-worn yellow and blue sapphire stones are commonly colour enhanced to obtain high prices. It is said as much as 80% or more such stones have been treated, and on cutting these stones the buyer will wonder how he/she could have made such a serious error in judging the original colour! Here is how it happens:
(a) Pale blue sapphire: "Do it yourself method" - The stone is wrapped in blue carbon paper with a plain piece of paper outside to prevent fingers from getting stained. Roll the stone around inside the paper, with your thumb, forefinger and index fingers pressed against the stone for several minutes. Wipe off the stone, and you can now market your stone for many rupees more than before! The blue carbon enters tiny pores or microscopic cracks in extremely small amounts and usually in only a few particular areas of the stone, but it is enough to ensure that the buyer is fooled. The buyer holds the stone against the normal light background, and the reflected blue from the particles behaves much as the "blue ink around the girdle of diamond trick". Alas, when the stone is cut, it is only the natural original fancy sapphire.
(b) Staining pale yellow sapphire: For this, you have to come to Sri Lanka as I doubt very much Canada has similar trees described below. But, the buyer visiting here could be from anywhere! There is a tree here called "Goraka" which is commonly found throughout Sri Lanka, and it has a saffron-yellow resin. (The leaves, and fruit of this tree are used in curries.) Using a simple penknife, the dealers PARTIALLY cuts a 1 inch cube, leaving the bottom uncut to act as a hinge. Note that this tree is soft and fibrous. The one inch depth is enough to access the interior. The yellow sapphire is then pressed into the tree with the thumb, and the chipped "door" is then pressed closed. The stone is left in the tree for several days, and when extracted it is wiped clean. The effect is better than that of sapphire treatment above, since the whole stone is stained a rich yellow colour. The stain is so strong it will mark clothing material permanently. You now have a very good coloured yellow sapphire (until cut!).
The above is quite accurate, as I watched such a "tree operation" taking place. I should like to wander around checking these "gem mine trees" somewhat like Robin Hood robbing the robbers.
Return to Top Knowledgeable buyers carry a small white cloth soaked with machine oil, or substitute, and every time they find a yellow or blue sapphire rough, they wipe the stone. Some of the carbon, or yellow resin stain, is easily seen on the white cloth and the buyer shakes his head and hands the stone back to the seller. Though faceted and rough rubies are commonly treated with "ruby oil" in Thailand, the local enhancement described above is applied only to rough sapphires.
IDENTIFICATION OF GEMSTONES WITH MINIMAL EQUIPMENT
Return to Top
This is the most difficult aspect of buying at a pola. With the excitement, heat and pressure all you can do when you suspect a stone is valuable or rare, is buy it so long as the price is right. You can test it later. At best, you have the stone you hoped for, and the worst is you have a synthetic or imitation. The following tips may help you, but the final decision is yours don't blame me!
COBALT SPINEL: A good specimen has a rich almost sapphire blue colour quite unlike the pastel blues of normal spinel, however colour lightens as the cobalt content decreases.
* Use the Chelsea filter for a quick but not conclusive test but be careful! The natural cobalt spinel will appear a red (or orange/red depending on cobalt content) colour similar to that of the synthetic cobalt doped stone;
* Spectroscope: The spectrum will show the cobalt spectrum of three broad bands in the orange/yellow/green, but in addition there is the natural blue spinel spectrum (diagnostic) with lines in the blue area which are not normally seen in synthetic spinel.
* Ultra violet: The natural spinel will be inert under LW and SW, while the synthetic will show chalky bluish-white under SW.
* Refractometer: Cobalt spinel may have an R.I. of around 1.718 rather than the normal Sri Lankan spinel R.I. of 1.712 still well below that of the 1.728 of synthetic spinel.
SPESSARTINE GARNET: This stone has more "fire", and is free of the numerous inclusions of hessonite. Examination with a 10x loupe will often reveal a delicate, wavy feather. The colour is normally strong orange and not the yellowish orange of hessonite. Visual gemmology will separate the two immediately: Look through the table facet with the CLEAN stone pressed as closely to your eye as possible, aiming at your illuminated penlight. If the light source looks as though it is in an orange, hazy "snowstorm with indistinct snowballs" it is Hessonite. If the light source is clear you will see each light source clearly and can assume it is Spessartine. (Note: Occasionally hessonite may not be very heavily included, however the light source will appear to have "radiating beams" surrounding it and the whole spectrum is nothing like the clear one of Spessartine.)
TAAFFEITE: Very rare, and unless you purchase directly from a dealer (at a high price), you can only hope to find one in a spinel parcel. Though confused with blue spinel, there is little in common except for the pale mauve colour. Taaffeite belongs to the hexagonal crystal system, has double refraction, etc. while Spinel is in the cubic system and singly refractive. Taaffeite has more "fire", but the double refraction (0.003) is so small that it is impossible to detect using either the polarizer lens, or visual gemmology (unless you are experienced). If you have a polariscope you can quickly note if the stone is doubly refractive, and of course the refractometer will confirm either way. When I see a pale mauve spinel I buy it and test it at home the price is quite low and the Spinel is worth it. You may be lucky!
SINHALITE: The "honey" colour (orange/brown) is very similar to the brown zircon, so check carefully! Sinhalite is found in small to large sizes (e.g. up to 8 carats or more), and the only certain "on the spot" test to weed out zircon is to use your spectroscope. Similar coloured tourmaline may be found, but by viewing daylight through the table facet (light colour), followed by viewing through girdle (dark) you will instantly note the difference that identifies this stone. Anyone skilled in visual gemmology can identify the respective double refraction indices of sinhalite (0.038), zircon (0.059) and tourmaline (0.018).
GREEN SAPPHIRE: Recently there is a sudden influx of green sapphires. These may be heat treated sapphires being brought in from Thailand or elsewhere. The stones are a good green colour, but the cost is lower than natural green sapphires and you should bargain accordingly. I examined a few with a lens and the telltale uniform small cracks were present in each stone.
BLACK STONES WORTH BUYING: Kornerupine cat's eye stones show excellent chatoyancy, and are fairly rare. You can buy these several at a time on occasion either in a small parcel or glass display box. Star diopside is another black stone worth buying (at a low price), with excellent four-ray asterism. Black star sapphire with its perfect six rays, and large sizes are a little expensive but still a good buy. (I have not found any of these sapphires at the Polas, but purchased a beautiful one in a Colombo shop.) Black "caw caw" stones: So-called because of the colour being similar to that of a crow. These are very cheap, dark blue sapphires that appear to be black, and traditionally wards off evil eyes. The majority of Sinhalese (particularly babies) wear rings, amulets, or necklaces adorned with these stones. (At first I thought the name was ca- ca and I laughed every time I heard it. It took a full year before finding out the pronunciation and meaning!)
IMITATIONS: Deep blue "star sapphire" and deep red "ruby" are obvious because of four major features combined: Size, colour, asterism with thin perfect rays on the surface of the stone, and very low cost. A natural stone similar to these imitations would cost hundreds, or even thousands of dollars should such rare quality stones be found!
GLASS: These "pit glasses", faceted or rough, are easy to identify and they make good study specimens for your collection.
HOW TO IDENTIFY PIT GLASS:
Return to Top
* Pit glasses have dramatic vivid colours (usually green, red, blue, yellow). When faceted, these glasses often imitate citrine, aquamarine, topaz, etc., and have such a shocking colour one wonders how they get away with it. Note, however, that when I came to Sri Lanka I did not know the difference and could easily have been fooled. It was only thanks to my accompanying gemmology tutor that I was spared the embarrassment.
* HEFT (light for their size), and COST (cheap for the size).
* Check the stone with your 10x lens and you should see the bubbles and swirls that identify these glasses.
* Visual gemmology, or the polarizing lens, will show single refraction. The only other common singly refractive stones in Sri Lanka are garnet and spinel, and the glasses are usually too big to be either. (Sorry, no diamonds, but they do have CZ's!)
* Glass is warm to the touch, natural crystals are cold. Using tweezers (to avoid heat transfer from fingers) touch the CLEAN stone against your tongue or inside upper lip to test.
* If the stone is clean and well polished, a drop of water will spread on glass but keep its dome shape if the stone is crystal. This is due their differing atomic structures (random in glass, and organized in crystal.) Anecdotes:
* On one of my shopping expeditions a man offered me a blue star sapphire, 30 cts, for 25,000 rupees. I laughed and jokingly offered 2,000 rupees, and he agreed as I was leaving! This confirmed the stone to be synthetic, and I refused the offer. Now I wish I had bought it for study purposes. Also you may note that I broke the unwritten law of making an offer and refusing but then I was justified and my popularity rating was unimportant.
* Importance of testing: A beautiful, brilliant cut aquamarine weighing 30 carats passed the Chelsea filter test, e.g., it produced a good green colour. The price was excellent, and I hastily sealed the deal. On arrival home I tested it and discovered it to be beryl fusion glass! I ignored my own advice above: The size (too large), cost (too low) and the cut (a natural stone of such colour should have been given the step or emerald cut). So once again, it is impossible to overemphasize the importance of taking your time, studying the stone, etc.
Return to Top
Though this article is primarily about coloured gemstones, it is obvious many visitors will want to buy gold jewellery. With this in mind, the following information should help. Gold prices are controlled and adjusted daily in accordance with the world market, however labour charges are cheaper than in the West and the gold jewellery fashioning is superb. The people of Sri Lanka invest in 22K gold jewellery, and many frown on anything less. Banks treat gold as a currency, e.g. they accept gold in the same manner as pawn shops, but only if it is 22K. Once or twice a year banks hold an auction for all the unclaimed jewellery, and by checking the classified advertisements in the English language newspaper, one can end up purchasing excellent jewellery at a good price. 22K Gold is normally sold, and priced, by the gram. However, in Sri Lanka many dealers refer to an item as being, "one sovereign, or, "one and a half sovereigns." One "sovereign" is composed of 22K gold, and weighs eight grams (e.g. weight of the former British gold sovereign). It is a good idea to remember this so you do not become confused when dealers use these terms. Sovereign gold is not in demand by foreigners who are accustomed to 10 - 14 - 18K gold, probably because they feel it is "too soft". Soft it may be, but bearing in mind the fact people do not wear such luxury items regularly, 22K is quite durable providing the owner is careful. I would recommend it for the following reasons:
(a) It is always available, and at a lower cost (gram for gram) than the lesser quality gold. In Sri Lanka they often use the term "wastage" to explain why there is so little difference in the cost between 22K and 18K. Apparently this "wastage" is incurred when they have to make jewellery on demand, and they must use the leftover gold at some future date when an equal amount of 18K gold is required. Sounds like rather a weak argument, since you are paying for the "wastage", and the future buyer will pay again! But, that is the way it is.
(b) 22K gold is transformed into beautiful earrings, bracelets (called "bangles" locally,) chains for pendants, and rings that are incomparable. They have maximum metallic high lustre, beautiful colour, and are machine-faceted so that they glitter as if imbedded with gemstones! I have lived nine years in Arabic countries where 18K gold is the norm, and I have never seen gold fashioned so magnificently as in Sri Lanka.
(c) Though I would recommend 18K gold for signet rings, or wedding bands that would be worn daily, the "softness" of 22K does not apply to items that are worn only on occasion. My wife has beautiful 22K jewellery that is very much admired "back home," and there is no sign of wear and tear. So, buy some 22K gold jewellery for your loved one and she/he will be the envy of all! WARNING: You should be aware that all the Sea Street "rubies" and "emeralds" adorning rings and bangles I have seen, are synthetics or imitations. The dealers will tell you the truth if you ask them, so they are not out to cheat you. Should you not ask and go home thinking these stones are natural you will have a nasty surprise when you have your goods appraised.
WHERE DO I BUY GOLD JEWELLERY?
Return to Top
Sea Street, in the "Pettah" area of Colombo is a narrow, crowded old street lined on both sides with a large number of small gold jewellery shops. There are more shops than you could possibly hope to visit properly in one day. The dealers are Tamil business men, largely from India, and are very sharp and clever to deal with. You must bargain hard, and unfortunately the "plateau" method used for gemstones does not apply here. But there is a percentage tacked on to the prices to cover tour guides and touts, so bargaining is necessary.
Return to main page of Gemology World