RUBY
The world's best Burma ruby originates in the lawless region where Laos, Burma, Thailand and China meet. This area has become known and widely romanticized as "The Golden Triangle". The location is off the beaten track. A large amount of wealth in rubies, jade, silver, lumber and above all, opium, begins its journey in this "Golden Triangle". It is the home of drug warlords, arms dealers, insurgent armies, latter-day slave traders and plain, old-fashioned bandits.
Without a doubt, the best and most sought after ruby in the world by collectors is mined in Mogok, Burma (now Myanmar). The reason these gems are coveted is that they glow and tend to look good in all lighting conditions. This glow is the direct result of fluorescence. When fluorescent gems are struck with ultraviolet light, the gem adds an extra punch. Burma stones tend to be light and bright compared to ruby from other sources.
Although there are thousands of different shades of red, for the sake of argument, let's categorize Mogok Burma ruby into three groups:
- The ultimate color is what is referred to as "pigeon blood", "stoplight red", or "cherry-lifesaver red". The primary color is red and the secondary color is orange, purple, or pink. These stones are ultra-rare and command price premiums. They are sought after by an awaiting international gem market.
- The second major color is best described as "electric magenta". The predominate color is red and the secondary is pink. These beautiful stones are light-toned, bright, and vibrate with color.
- The final group is "hot electric pink" or "day glo pink" gemstones. These stones tend to look good even without any direct light. The primary color is still red, but with less red than the "electric magenta" colors.
Which color is best for collectors? This is a controversial subject among dealers and collectors. Some collectors love strictly one group, for example the "pigeon blood" reds, to the exclusion of the other groups. Some collectors strictly collect the pinks or magentas. Some collectors believe it is too difficult to trade in only one group and collect the finest examples of all three groups. This is probably the most prudent strategy. For collectors on a budget, you can start with the hot pinks and work your way up through the magentas to the reds as your finances allow.
The finest one carat, unheated, Mogok Burma rubies cost between $2500-$15,000 per carat. Two carat Mogok Burmas are available from $5000-$30,000, three carats between $10,000-$40,000 per carat. Four carat Mogok Burmas can easily exceed $50,000 per carat.
Ever since Burma's Communist leaders shut off the country in 1962, Mogok Burma ruby has been an endangered species. Even before 1962, the famous Mogok tract production was in sharp decline. Mogok is 4,000 feet above sea level and frequently has over 100 inches of rain a year. It has been worked since 1200 A.D. Gem poachers worked this area by night. There is some limited production today due to the Burmese leaders present strategy of attempting to "open the country and acquire hard currency". However, the Burmese government is well known for constantly changing their economic policies.
Today most miners have left Mogok and are working a new find in Mong Hsu (pronounced "Mine Shu"). This mine was discovered in 1991 and the gems hit the US market in 1993. The mine is located 60 miles south of Mogok and sits in rebel territory. The Shans, an ethnic tribe at war with the Burmese Central government, control this area. Nevertheless, the Burmese government has auctioned off the land for mining and is even involved in a few joint ventures. Although the vast majority of the ruby production is rejection grade, it has been estimated that enough ruby has been mined to produce sales between $100-$200 million. Most of the goods are smuggled across the Thailand border at Mai-Sai or Mae-Sat. Then they are sent to Chantaburi, Thailand for heat treatment. Rough Mong Hsu tends to have a color-darkening blue hexagonal zone that runs through the center of the stone and looks like "bad garnet". After cooking, the stones turn into bright, lively red gems. As a matter of fact, most of this production looks exactly alike in color and tone. The largest Mong Hsu known is an eight carat gem that was rumored as being offered for $50,000 per carat. As a general rule, they sell in price similar to Thai ruby. Recent mining history indicates this find may be small and short-lived. The Mong Hsu material is presently involved in a controversy. We have always known this stone was heat treated. The American Gemological Laboratories (AGL) contends 70% of these rubies are also fracture-filled with intent to deceive dealers, jewelers, and the final consumers. The Gemological Institute of America (GIA) says they are not fracture-filled. Therefore, the prudent course at this stage is to only collect Mogok Burma ruby, not Mong Hsu. However, Mong Hsu ruby may hold a special place in certain portfolios and in jewelry if you want a red stone but do not have the funds for a Mogok.
Due to the severe shortages in Burma production, the majority of rubies bought and sold today are from Thailand. A few Thai families firmly control every aspect of marketing; from mining to cutting and heating. If you are looking to collect a ruby on a relatively moderate budget, many experts predict this stone may, in the long term, eventually gain the acceptance Burma ruby now holds. Almost all of these stones are cooked. The majority of Thai stones tend to have purple secondary colors as compared to Burmas. Occasionally, you can find an intense red/orange that is highly desirable. Also, you sometimes find a Thai ruby with a lighter tone similar to Burma, (like those from the now defunct Bo Rai mine) that is highly desirable. Some Thai rubies approach Burma in appearance and are highly sought after. As a general rule, one carat Thai stones will sell between $1000-$7500 per carat. Two carat stones can range between $3500-$15,000. Three carat Thai ruby can cost between $4500-$20,000 per carat. Four carat or larger Thai stones can exceed $20,000 per carat.
Another interesting ruby worth noting is the star ruby. Rather than being faceted like most ruby, these stones are cut cabochon. Until recently, these stones always sold for more than the faceted ruby. In the late 19th century, three carat star rubies went for $3000 per carat. Stones found today that could be cut into stars are routinely heated to dissolve the rutile and then faceted. Therefore, fine stars are rarer than rare. Also, US buyers must compete with the Japanese and the Europeans who will pay any price for these gems. Star rubies were the rage until the 1960s, but have since fell out of favor. If you want to see an outstanding collection of stars, go to the American Museum of Natural History in New York and view the J.P. Morgan collection. In searching for these gems, follow these guidelines:
- The six legs of the star should be sharp, not wide and blurry.
- The star should be centered.
- The main ray should run lengthwise.
- The star should be silvery or milky white.
- In an ideal world, star ruby should be the color of a Marlboro cigarette box. However, if red stones are discovered in Mogok Burma they are usually faceted and sold for serious money. Most star rubies today are red/pink or pink/red.
- From a clarity standpoint, the stones should be semi-transparent. Like cat's-eyes, the stone should not be too flat on the top or too heavy on the bottom.
SAPPHIRE
Today, Kashmir sapphires remain at the top of the gemstone hierarchy. The blue they possess is rich, velvety, and serenely soft. Originally discovered in 1882, the stones were so plentiful the locals would use them as flint stones. By 1925, the mines were nearly depleted. Kashmir is a mountainous region in northern India. It is about 86,000 square miles and has a population of over 6 million. Due to its beauty and towering mountain ranges, it is often called the "Switzerland of India". Much of the production today is smuggled out. The region is so inaccessible that it can only be reached by foot or mule. Mining is sporadic and only attempted for a few weeks in the summer. In the winter, temperatures can fall below -45 degrees F, and blizzards can last for weeks. During the Depression, fine Kashmir blues sapphires never sold for more than $500 per carat. These stones are so rare, only a few may be available at any one time. Today, you can easily spend $5000-$10,000 for a carat size gem, $10,000-$15,000 for a two carater. Larger stones can go up to $50,000-$60,000 per carat.
Mogok Burma sapphire is almost as rare as Kashmir sapphire. The production of Burma sapphire is exactly the same situation as Burma ruby. As a general rule, you are looking for a milk-of-magnesia electric blue. Deduct 25% off the Kashmir prices to arrive at the price Burmas are trading for. Add 40% for an ultra-rare uncooked gem. Many collectors contend that Burmas will eventually reach price parity with the Kashmir gems, and are buying whatever is available.
A major source for blue sapphire today is Sri Lanka. In the mid-1970s, the Thais experimented in heating these gems to permanently improve their color. Instead of using low temperature, charcoal-fire heat, they bought high-temperature kilns and sophisticated furnaces. This caused the milky yellow rough (called Geuda) to turn blue and it also caused cloudy stones to turn clear. This new technology actually more dramatically assisted commercial-quality blue sapphires than collector sapphires. Today, with the exception of a few fine stones, 99% of all blue sapphire is cooked. This market has actually turned into a two-tiered market; cooked vs. uncooked. Expect to pay about a 30% premium for a non-cooked blue sapphire. As a general guideline, Sri Lanka blue sapphire sells for 1/2 the price of Kashmir stones. The finest one carat Sri Lankan stones can range from $1000-$3000 per carat. Two to five carat sized stones sell between $3000-$7000. Over five carats, stones can reach $10,000 per carat. For moderate budget collectors, stick with the finest blue colors.
There are also new blue sapphire sources in Africa and Laos. Some of these stones rival the Sri Lankan goods. Thailand and Australia also produce blue sapphire, but they are overly dark, and should not be collected. They are simply too abundant.
Finally, like ruby, when some rutile-filled stones are cut cabochon they produce a six-sided star. Regretfully, because the Thai cookers have discovered how to remove the rutile by heating these gems, they are becoming very rare. Also, in the 1940s, Linde, a division of Union Carbide, began manufacturing synthetic star sapphires. Of course the synthetic star's legs were perfect, and consumers began demanding the same from the natural gems. This is really too much to ask from a natural gem. Nevertheless, if you are interested in collecting natural star sapphires, here are some tips: The quality of the star is everything. The star is more important than the color. Grayish sapphires tend to have better stars than the top blues. Gray stones tend to be better cut than the blues. The blues tend to have sagging bellies, while the grays are flatter. This is because the blues are more translucent, and cutters must keep more of the original rough to retain a star. Therefore to collect fine blues, expect to pay for extra weight. However, on the positive side, the consolation is that blues with fine stars are rare, and sought after by collectors worldwide. If one or two of the legs of a star are missing in a 10 carat blue, expect to pay $3000 per carat. If the star is perfect, double this price-if you can find one. Prices ease a little at 5 carats or less. For collectors on a budget, you can buy light blue or gray stars for 1/10 of these prices.
BURMA SPINEL
Spinel is probably one of the most misunderstood, yet prized, gems in the marketplace. From the beginning of time, it was assumed all red stones were rubies, from the Latin for red "ruber". In 1783, mineralogist Rome de Lisle discovered there was a gemological difference between ruby and spinel. The famous "Black Prince Ruby" and the "Timur Ruby" in the British State Crown Jewels are actually high quality, and priceless, spinels. In the early 1900s, scientists devised an inexpensive method for creating synthetic spinels, which is why many inexpensive birthstone rings are actually synthetic spinels. The amount of fine spinel in today's market is severely limited. These gems are mined in and around Burma ruby as crystals and pebbles in placer deposits, where they accumulate because they resist weathering. It is amazing how many spinel turn up in ruby shipments at the border. Only knowledgeable experts can discern the difference. These gems are 200 times rarer than ruby, possess more fire (dispersion), and are available for about 25% of the price of rubies. For collectors, stick with gem, blood or day glow reds, hot pinks, and flame oranges. Any spinel over 2 carats is large. Occasionally, one finds a ten carat spinel. Some collectors collect one color, and others collect all the colors. Besides the most common colors, spinel also is discovered in blue, purple, and color-change. Pastel spinel is mined Sri Lanka. These pastel stones are priced in the $50-$500 per carat range. There is also new spinel production from Viet Nam and East Africa. With minor exceptions, these gems are not as intense as the Burma gemstones and should be avoided by collectors.
KENYAN TSAVORITE
This beautiful green garnet was discovered in 1968 in the Tsavo National Game Park. When Campbell Bridges discovered the green garnet, he thought he had discovered a new source for demantoid garnet. Demantoid is the only other green garnet (once mined in Russia) and now trades from $10,000 per carat and up. Many experts believe tsavorite will be the next demantoid, extinct and ultra-rare. It is often called the Rolls-Royce of greens at Cadillac prices.
From an collector standpoint, tsavorite is 200 times rarer than emerald, is cleaner, more brilliant, is not altered with with oil or heat. Plus, tsavorite is available for 1/4 of the price of emerald. Today there are four small mines operating in Kenya. Any stone above three carats is considered large and exceedingly rare. Sporadic production probably means higher prices. The tsavorite pockets are small and unpredictable. Only one or two mines can be counted on to be operating. When collecting tsavorite look for a lime Jell-O green. Avoid light soda-bottle green or overly black stones.
TEN RULES FOR GEMSTONE COLLECTING
The following rules are critical if you are going to be a successful collector:
- Learn to love gems for their beauty, portability, and privacy.
- Align yourself with a knowledgeable expert. This can be a dealer, a wholesaler, or a retail jeweler. If you are going to deal with a retail jeweler, tell the jeweler your plan, and request that he work on a smaller mark-up than normal.
- Collecting gems is primarily suited for the sophisticated individual with a substantial portfolio. Place no more than 10%-15% of your portfolio in gems. A beginning portfolio will cost you $10,000 (one or two gems). A well-diversified portfolio will run between $25,000-$100,000, or higher.
- Do not buy a colored stone without an American Gemological Laboratory (AGL) Colored Stone Grading Report. For beginning collectors, this is critical. This lab is considered the final arbitrator in "country of origin" and treatment issues. If you are paying the price for a Kashmir sapphire, Burma ruby, or Colombian emerald, make sure the stone is accompanied with an AGL certificate stating the country of origin.
- Do not buy a diamond without a Gemological Institute of America (GIA) Diamond Grading Report. This is the only laboratory that is internationally recognized. If your diamond has this grading report, no one will ever argue with the lab's grading of the stone. If you are collecting colored diamonds, this grading report is vital.
- Be sure you are buying at near-wholesale prices. Some good sources of information.
- View your gem portfolio as a long-term hedge.
- Allow time to liquidate. Gems are similar to real estate, rather than precious metals. Proper portfolio planning can alleviate this potential problem. Gems are instantly liquid, but at a discount.
- Buy the best you can afford. In up markets, "the best appreciates the fastest".
- Beware of boiler room gem scams. Remember, if it sounds too good to be true, it usually is. Watch out for Canadian firms with fake "look-alike" certificates and bogus price lists. Never buy a stone that is sealed in plastic or a lucite box.
CONCLUSIONNo one knows what the future will hold. It is impossible to predict, if by collecting fine gemstones, your portfolio will repeat the success of Mr. Hancock's. A great deal of collecting is timing and luck. The philosophies of collecting gemstones are varied and complex. Some collectors only collect one specific gem. For example, some collectors purchase every spinel, emerald, or colored diamond they can afford. They are viewed as specialists. Others collect one specific color such as green; they collect emerald, demantoid garnet, and tsavorite. Some collect one species; for example, every color of sapphire. Others collect the finest specimen of every collectible gem available. They believe diversity is the key. Some collectors use a combination of these philosophies.
Irrespective of which portfolio theory you believe, the key is to collect gems you love. The buying, the possessing, the occasional viewing of your gems in your safety deposit box at the bank, should give you a feeling that is indescribable. The true goal of collecting is the pride you incur with owning some of the finest gems presently available in the world. Building a collection of fine gems should be fun.
If you buy, sell, and trade properly your gem collection should grow and grow. In a sense, it is almost a forced savings plan, but often viewed by collectors as considerably more fun than looking at a bank savings account balance. As time passes your gem portfolio may grow in value. If economic conditions change and inflation heats up, watch out, your portfolio may be worth a fortune. These two conditions, time and inflation, made Mr. Hancock's $20,000 investment worth $1 million.
However, even if you are not the next Mr. Hancock, the thrill of the chasing fine stones and the thrill of ownership is unparalleled in the collecting arena. The rest is just gravy. Good luck and have fun!
DIAMOND
Diamonds are the best known and most traded gemstone. Very few individuals collect white diamonds. One exception are individuals who collect D-Flawless diamonds. This is the ultimate "pure white ice" diamond. In 1974, you could buy one of these stones for about $5000. They topped out in 1980 at over $60,000 per carat. Today, you can buy a carat sized D-Flawless for about $14,700 to $16,400 per carat. Some people collect them in various shapes, such as rounds, pears, marquise, radiants, ovals, and princess cuts. Others just buy rounds. Also, some people collect only important large white diamonds. Collectors buy them for their history (perhaps someone famous owned the gem), or for their large size (any diamond over 10 carats is important).
The vast majority of collectors collect colored diamonds. No other jewel combines the rarity, beauty and sex appeal of a colored diamond. Let's face reality. The majority of white diamonds are not rare. The DeBeers cartel is the most successful cartel in existence. For over 60 years, they have convinced Americans that diamonds equate with love. On the other hand, colored diamonds are exceedingly rare, and are simply geological flukes. For every 100,000 D-flawless diamonds, there is probably one colored diamond, and it is probably not flawless. The beauty and the rarity of these gems has spawned unprecedented desire and unparalleled prices for these diamonds. If you are a collector, you can collect colored diamonds depending upon your financial resources. If you are in the highest economic circle, you can collect reds, pinks, greens, and blues. If you are moderate collector, you can own fancy yellows and oranges. If you are on a tight budget, you can specialize in browns, from cinnamon to coffee to light beige. One important fact to remember is that in colored diamonds, clarity is secondary to the intensity of the diamond's color.
RED DIAMOND
Red is undoubtedly the rarest colored diamond. Besides the .95 red diamond sold at auction in 1987, only a few others are known to exist. In the 19th century, a famous London jeweler owned a carat-sized red, which he bought for 800 British pounds. Is this the same stone as the .95? In the 1920s a 5.05 emerald cut was cut from a 35 carat piece of rough. This stone was cut by the Goudvis brothers in Amsterdam, after being found in South Africa. Rumor has it that occasionally a red diamond is found in Borneo. A .25 red oval recently sold at Christie's for $326,800 per carat. Red diamonds are almost priceless.
PINK DIAMOND
Pink diamonds have always been exceedingly rare. In the 16th and 17th centuries, India was the principal source of pink diamonds. Recently, a famous light pink Agra diamond was sold at auction for almost $7 million. This stone was documented as being a gift to Babur, the first Mogul emperor, from the Rajah of Agra, for sparing his life in 1526. It later belonged to the Duke of Brunswick, the greatest connoisseur of colored diamonds of the 19th century. In 1725, Brazil produced some light pink diamonds. The Star of Brazil is a 128.80 carat rose colored gem, which was cut around 1832 in Amsterdam. An Indian gem collector paid 80,000 British pounds for it in the 1860s. It remains in India today. In 1947, Dr. John Williamson discovered a 23.60 pastel pink round diamond in Tanzania. It was not until 1979, when Australia discovered a small vein of pink diamonds that things really got exciting. Instead of being faint or light pink, these new diamonds are hot pink. They are producing about a 100 carats a year. The majority of gems are under one carat. In 1989, the Australian mine, Argyle, sold two pinks over 3 carats. It is rumored these stones were sold for $700,000 per carat. Expect to pay over $100,000 per carat for a carat size pink.
BLUE DIAMOND
India was the main producer of blue diamonds from 1500-1700. This was the source for the 112.25 French Blue that later became the the infamous 45.52 Hope. Another famous blue, the 33.56 Wittelsbach showed up at a wedding in 1667, and ended up in Bavaria in 1717 with the ruling House of Bavaria, the Wittelsbachs. It is presently believed to be with a private collector in Germany. Today, new production of blues comes from South Africa or Australia. In order to understand pricing, here are some examples of recent auction prices. In October, 1994, at Sotheby's, a dealer representing a Hong Kong concern, paid $9 million, or over $460,000 per carat for a 20.17 blue diamond. In 1995, at Sotheby's, a 6.70 blue diamond sold for $3.52 million, or $525,000 per carat. The leading price per carat public sale for a blue diamond occurred in 1995-a 4.37 fancy deep blue diamond sold for about $2.4 million, or $569,000 per carat at Christie's.
GREEN DIAMOND
Besides the Hope diamond, the second most famous diamond is the Dresden Green. It is green and weighs 40.70. it is believed to have come from Brazil in 1725. It was purchased by Frederick Augustus the Second from a gem merchant at the Leipzig Fair in 1742. Since then, it has been exhibited for public display in the west wing of the Dresden castle. In 1983, a 8.19 rectangle green diamond was sold at Sotheby's for $396,000. In 1988, a 3.02 yellowish/green sold for $1.7 million.
YELLOW DIAMOND
Although faint yellow in white diamonds is not desirable, fancy intense yellow is sought after. Although India produced some yellows in the 16th and 17th centuries, South Africa today is the main producer of these gems. As a matter of fact, the first authenticated diamond found in South Africa was the 10.73 yellow Eureka. By 1900, South Africa had produced the 128.51 Tiffany, the 130 carat Colenso, the 228.50 DeBeers,and the 205.07 Red Cross. In 1996 at Christie's, a 8.45 fancy vivid yellow sold for $684,500 or $81,000 per carat.
Today, collectors can buy yellows in various shades from lemon yellow to taxicab yellow. The best pure yellow or orangish yellow will be called "fancy intense" or "fancy vivid" yellow on the Gemological Institute of America (GIA) grading report. These diamonds are rare and expensive. Slightly below these stones are the fancy yellows. These stones are more affordable but still quite yellow.
ORANGE DIAMOND
In an ideal perfect world, you should try to collect orange diamonds that look like a Halloween pumpkin. These pure diamonds sell for more than the yellows. A 8.93 fancy intense orange sold for about $1.9 million at Sotheby's. However, if you are looking for a bargain, focus on oranges with yellowish secondary colors. You can also collect intense oranges with just a hint of brown at substantially reduced prices.
BROWN DIAMOND
If you want to speculateon a fancy diamond at affordable prices, browns are a natural choice. The connoisseurship of brown diamonds may be in its infancy. In essence, these are the only colored diamond bargains left. Cardinal Jules Mazarin, the chief minister of France in the 1600s collected brown diamonds. In 1967, a 115.59 African brown pear shape was discovered. It was reportedly sold in 1983 for $900,000. You can buy coffee colored diamonds for $2000+ per carat. This is lower than many white diamonds.
EMERALD
Collectors are fascinated with emerald. This rare and exotic gem is also known as "green fire". Colombia is the main source of gem emerald. This South American country is one of the most dangerous and unstable places in the world. Many visitors recall the similarities between Chicago in the 1920s and Colombia today. With the highest murder and kidnapping rates in the world, cocaine cartels and a long-running guerrilla insurgency, Colombia is often referred to as "Locombia", or the mad country.
The two most famous mining areas are Muzo and Chivor. Muzo is located 100 kilometers north of Bogota. The district is hot and humid, and it constantly rains. Muzo and Cosquez are the major mines here. Emeralds are found in black calcium-rich shale. Most of the stones from these mines are horribly included. Chivor, which is northeast of Bogota, is in a rugged, almost inaccessible topography with thick, forest vegetation. The two major mines of this district are Chivor and Gachala. Chivor mine sits 2300 meters above sea level on a mountainside. Chivor was originally mined by the Chibcha Indians and emerald was traded from the Andes to Mexico until the mine was lost. Chivor was rediscovered in 1896. In this area the rock is black shale and sandstone. The Colombian emerald market is wide open. Although the Colombian government leases mining rights to private business, illegal mining is the rule, not the exception. No one even pretends to control the situation.
Which mine is better for collectors? The terms Muzo and Chivor are often used in the trade, not so much to determine the exact source of a gem, but rather to to describe the qualities of the emerald. "Muzo" is used to describe a warm, grass-green emerald, with yellow being the secondary color. "Chivor" stones are like the pine trees of Washington state, with blue being the secondary color. Certain collectors and dealers argue about which color is the best, but it is really a matter of personal preference. In top colors (3.5 to 4.5 AGL) , both types of these emeralds are highly desirable and expensive.
Emeralds are very included compared to most gemstones. Inclusions that would not be acceptable in ruby and sapphire are acceptable in emerald. The definitive identifier for Colombian emerald is the three-phase inclusion; solid, liquid, and gas. Even though the gem is typically mined with eye-visible inclusions (even at the collector level), emerald is the most popular colored gem in America. Probably 98% of all emerald discovered would be graded Heavily Included (HI) or worse at the AGL. Therefore, a Moderately Included 2 (MI2 from the AGL) is considered a relatively clean emerald.
Most collectors seek strictly Colombian emeralds. They spend decades buying the finest green and cleanest stones available. Occasionally, African and Brazilian emeralds are discovered that look exactly like Colombian emerald. These gems make sense to collect if you are an emerald connoisseur. If you have a moderate budget, you can purchase African emerald. As a general rule these gems are cleaner than Colombian emeralds but have a touch of black and gray colors. They trade at a 50% discount to Colombian stones. Finally, if you are on a limited budget, occasionally Brazil produces nice stones at about 1/2 the price of Colombians. As a general rule, Brazilian emeralds are green/black in appearance.
Commercial quality Colombian emeralds can easily range from $500-$2500 per carat for one carat stones. High jewelry quality ranges from $2500-$5000 per carat. Gem, one carat emeralds range between $5000-$10,000 per carat. The finest color, four carat or larger Colombian emeralds can easily fetch $20,000 per carat. A ten carat, gem emerald can exceed $50,000 per carat. If an emerald is AGL certified as Lightly Included, add 50-100% to these figures.
Approximately 99% of all emeralds are treated. Similar to the heating of ruby and sapphire, this is perfectly acceptable. Emeralds have been oiled for centuries. Treatment is only possible when inclusions break the surface. Clear oil is forced into surface-breaking inclusions, thereby reducing the visibility of inclusions. Oiled stones tend to fluoresce a pale yellow. Some collectors view this process as akin to buying fine furniture. Once a year it is brought into the manufacturer for a re-oiling. A new treatment for emeralds is opticon. Some dealers contend opticoned emeralds have a better finish, are more durable, and the treatment is permanent. Opticoning uses the same theory as oil, but inclusions are filled with a thick epoxy instead of oil. The stones are sealed with a thin coat. A brand new treatment was introduced in 1997 named Gematrat. They state that their filler "de-emphasizes" the visibility of fractures but does not hide them. The GIA is presently working on a extensive research project that will include studies on emerald treatments and their effectiveness and durability to as many different conditions as they can reasonably test. Suffice to say, if you collect emeralds, you should be aware they are probably treated in some fashion.
