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Alexandrite Facts Birthstone Info
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Alexandrite Information |
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THE TRADITIONAL BIRTHSTONE for JUNE |
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| The 55th ANNIVERSARY STONE | |
MOH's scale of hardness : 8-1/2 |
Toughness : Excellent |
Refractive Index : 1.746-1.755 (+.004,-.006) |
Specific Gravity : 3.73 (+/- .02) |
| Alexandrite changes color from green in daylight to red in incandescent light. The first time you see it, it is hard to believe your eyes! Alexandrite was first discovered in Czarist Russia, in the Ural mountains, on April 3 1834, when several crystals were found in Tokovanya deposits. The name "Alexandrite" was coined by mineralogist Dr. Nordenskjld (Finnish by birth but he worked for the Russian Czar). Since the old Russian imperial colors were red and green it was named after Czar Alexandr II on the occasion of his coming of age in 1842. Genuine Alexandrite is one of the world's rarest and most coveted Gemstones, it's so rare that most people have never even seen a genuine Top Quality Alexandrite. Alexandrite is in the Chrysoberyl mineral family and is one of the most fascinating gemstones throughout history. Alexandrite is the variety of Chrysoberyl that displays a change-of-color from green to red. A distinct color change is the primary qualification for a Chrysoberyl to be considered alexandrite. Although alexandrite is strongly trichroic, its color change has nothing to do with pleochroism. Instead, like all other color-change gems, it results in a near-equal transmission of the blue-green and red portions of the spectrum, coupled with strong absorption in the yellow. Thus its color is dependant on the spectral strength of the light source. Incandescent light is strongly tilted to the red end, thus causing alexandrite to appear reddish. Daylight, is more equally balanced. Since our eyes are most sensitive to green light, the balance is tipped to the green side. The strength of the color change is related to the difference in the areas of transmission, relative to the absorption in the yellow. The greater the difference, the stronger the color change. The color is actually caused by Chromium. A color change occurs in very few gemstones. For alexandrite, the quality of the color change is paramount. While the holy grail is a gem whose color changes like a traffic light from green to red, such a stone has yet to be found. In fine examples, the change is typically one from a slightly bluish green to a purplish red. The quality of color change is often referred to by dealers in a percentage basis, with 100% change being the ideal. Stones that display a change of 30% or less are of marginal interest and are arguably not even alexandrite. Significant brown or gray components in either of the twin colors will lower value dramatically. The natural color change in Alexandrite ranges from various shades of Green (blue-greens, kelly-greens, olive-greens, teal-greens, etc.) when the gem is under "fluorescent" lighting, or in natural outdoor light "in the shade" (not direct sunlight)... then the color changes to various shades of Red (burgundy-reds, purplish-reds, reddish-purples, violetish-purples, amethyst, etc.) when exposed to light in a room with only incandescent light, tungsten light, or candlelight (a flashlight will bring out the color change too). To get the maximum color change effect the gem is best viewed in a dark room with no outdoor light at all, then turn on a fluorescent light to see the green shade, then turn on a standard incandescent light bulb with the fluorescent light off to see the reddish shade. You can cycle the lights back and forth to see the distinct color change. Alexandrite will normally darken when taken out into direct sunlight, since it is subjected all the colors in the spectrum, also if subjected to several types of lighting sources at the same time the colors may twinkle with both the red and the green color bouncing around different facets in the stone. When the primary color has a bit of brownish in with the green, this is due to the bleeding of the two colors. Typically this is referred to as the percentage of color change. The higher the color change percentage, the more expensive the gem. When the color change from fluorescent light to tungsten light is not an obvious color change from one of the various shades of green to one of the shades of red, the gem is usually called "alexandrite like" or a "color change Chrysoberyl" since it does not quite have the distinct greenish to reddish color change to be called "Alexandrite". In terms of clarity, alexandrite is comparable to ruby, with clean faceted stones in sizes of one carat being rare and sizes over a carat and especially above 2 carats are extremely rare. Negative crystals and parallel rutile silk are common inclusions. Clarity, however, is a minor issue, as long as the inclusions do not affect the stone's durability. The color change is what represents the majority of the gem's value. Color, brilliance, and cut (in that order) are the 3 things that primarily affect the gem's final price. The more vivid the colors of a color change, the more valuable the gemstone. Ideally, you want a dramatic color change with a medium to medium-dark tone and intense color. In the market, Alexandrite is found in a variety of shapes and cutting styles. Ovals are cushions are the most common, but rounds are also seen occasionally, as are a few other shapes. Alexandrite can be found in jewels of the period as it was well loved by the Russian master jewelers. Master gemologist George Kunz of Tiffany was a fan of alexandrite and the company produced many rings featuring fine alexandrite in the late nineteenth and early twentieth century, including some set in platinum from the twenties. Some Victorian jewelry from England features sets of small Alexandrite stones. The original locality for alexandrite is Russia. Russian Alexandrite is extremely rare, the original source in Russia's Ural Mountains has long since dried up after producing for only a few decades. A few Russian miners are still working those trailings there in the Urals, and they are finding a few fine gems, but only in very limited quantities. We secure rare Russian gems from the Cheremsha and Malyshevskaya mines in the Ekaterinburg area of the Ural mountains as soon as they are found and made available to us. Some are small stones, less than a carat, but they all have a dramatic color change. Color change gemstones of Russian origin like this is particularly rare and highly valued by collectors. In 1987, an important new deposit was discovered at the Hematita mine in Nova Era, Brazil. Until this find, Brazil was only known for it's inexpensive gems. The old Hematita mine is still in production, but the new owners are finding it necessary to dig deeper into the mountain. We have access to the finest Alexandrite from these mines. At the present time there are only limited amounts of these goods on the market, and no one knows how much more the mine can produce, but the material presently is of very high quality. This Brazilian Alexandrite shows a striking similarity to the fine Russian gems, having an attractive color change from bluish-green to raspberry like purplish-red. These Brazilian mines have also virtually dried up after producing for only a few years, so they too are also in very limited quantities. These also remain extremely rare and expensive. Since we have have direct access to many of the original stones taken out of the mines we can offer them to you, a few of which are larger stones over a carat. We have also secured some of the finest Alexandrite from Sri Lanka. Many of these fine gems are from the Rakwana area, and they are absolutely stunning, changing from a vibrant bluish-green to a very nice reddish-Purple. We also usually have a few fine specimens from the Ratnapura region. These fine gems have a very good color change also, but it's usually a little more of an olive green changing to a purple stone. Not quite as dramatic as the Russian, Brazilian, and Rakwana material, but very nice indeed. The lower price per carat makes this choice a little more obtainable. The availability this fine material on our website means a new generation has the opportunity to own this beautiful and rare gemstone. Alexandrite stones have also been found in Zimbabwe, Burma, Tanzania, Madagascar, and India. When evaluating alexandrite, pay the most attention to the color change: the more dramatic and complete the shift from red to green, without the bleeding through of brown from one color to the next, the more rare and valuable the stone. The other important value factors are the attractiveness of the two colors - the more intense each color is the better - then look for the clarity, and then the cutting quality. Alexandrite is one of the worlds most expensive gems, with prices similar to those fetched by fine ruby or emerald. But like all gem materials, low-quality (i.e., non-gem quality) pieces may be available for a few dollars per carat. Such stones are generally not clean enough to facet. Because of the rarity of this gemstone, large sizes command very high premiums. Facet-quality alexandrite rough is extremely rare. Thus even the very small stones less than 0.5ct. (melee) can sell for thousands of dollars per carat. Any fine faceted alexandrite around one and a half carats or especially above two carats should be considered quite large. Stones of quality above five carats are extremely rare. We do not sell Synthetics. To assure you that you are getting a genuine Alexandrite from us, we normally provide you with a Gem Identification Report from our in-house gemologist, or a reputable Independent Gem Laboratory. The cost of Independent Gem Reports are included in the price of the gem if the report is listed. Our smaller Alexandrite gems can also come with a "Statement of Sale and Evaluation for Insurance", that includes the specific details on that particular gem as our guarantee of authenticity. Alexandrite is an excellent investment stone since it is definitely considered a "Very Rare" gem. TREATMENTS - Typically Alexandrite is not treated since it would adversely affect the natural color change phenomena. NOTE: While true synthetic alexandrite does exist, the vast majority are actually a synthetic color-change sapphire, colored by vanadium, not synthetic alexandrite. Since synthetic color-change sapphires have been made from about 1909 onwards, it is entirely possible to have a piece that could be classified as an antique. Indeed, many a traveler has returned from a third-world trip with what they think is natural alexandrite, only to later discover (or have their heirs discover) that what they have is a cheap synthetic sapphire worth but a few dollars per carat. If you own a gem that you suspect is an alexandrite, and you are wondering how to tell the difference between synthetic and genuine alexandrite, we recommend you send the stone to a reputable Gem Laboratory and ask for a Gem Identification Report. Please don't call and ask, we can't tell you anything over the phone except that you need to send the stone to a reputable Gem Lab, typically a local Jeweler can't do this. |
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