Sapphire is any gemstone-quality corundum that is not red. The red variety of corundum is also known as ruby. When colour is not specified, sapphire refers to the blue variety. Pink, yellow, green, white, and parti-colour (multi-coloured) sapphires are often valued less than the blue variety of the same quality and size. Yellow or orange corundum is known as “golden sapphire” in the trade.

However a pink-orange sapphire, called a padparadsha, is highly prized. There has also been a recent surge of interest in pink sapphires. Sapphires are mostly found in many countries especially in Asia such as India, Sri Lanka, Thailand, Myanmar, and Cambodia. Impurities in the crystal structure gives rise to the colour variations, with different impurity chemical elements giving the different colours that can be found. Pure sapphire is colourless. Traces of iron and titanium give sapphires a blue colour. With a hardness of 9, surpassed by only diamonds(10), the crystals are exceptionally hard. Gem quality sapphires and rubies occur naturally and can be easily and cheaply produced in the laboratory. The chemical compositions and physical properties are identical to the natural sapphires. The tell-tale sign of synthetic verneuil sapphires is the crystalline growth lines which are usually curved due to the pulling during the accelerated crystal growth process. Star Sapphire A version which shows an asterism is called a Star sapphire. Although natural sapphires can show an asterism, the shape of the star is usually somewhat irregular and sometimes indistinct. A manufactured star sapphire called the Linde Star shows a very regularly-shaped and distinct asterism because the formation process is more tightly controlled than the natural version. Blessed is the corundum that contains rutile. Not only does this mineral produce asterism in sapphires, it also acts as a bluing agent when combined with iron. There is only one drawback. Rutile can't perform both feats at once. It has to be in different chemical states to make stars and to make colour. If left in its undissolved state where it clusters in dense bundles of microscopic needles, abundant rutile causes corundums to become anything from translucent to opaque. Usually corundums with heavy concentrations of rutile have a milky appearance, which is why it is called "silk" in the trade. Fortunately stones with partially dissolved rutile have redeeming gray and light- to medium-blue colours. When cut into cabochons, these stones frequently reflect light along their domes in a six-rayed star pattern - the result of corundum's six-sided crystal structure. Star Sapphire displays a sharp six-rayed star in its center, commonly known as asterism. It appears in bright lighting and the quality depends on the sharpness of star, symmetry of the rays, and the body color. The American Museum of Natural History in New York City houses the largest cut star sapphire, the 543-carat "Star of India", and the "Midnight Star", a black star sapphire. The single most important factor in determining the value of sapphire is its color. Even the most expensive sapphires have inclusions and are not clear like diamonds. Fine sapphires of good color and clarity are very rare. Sapphires with medium and dark medium tones are considered the best and the too dark and too light sapphires have considerably less worth. The most valuable of the blue sapphires is actually violet-ish blue. Quality in Star Sapphire Since star sapphire is first and foremost a phenomenon stone, the quality of the star logically means more to jewellers and consumers than colours. It is hardly surprising that star specialists like David Cohen report selling three times as many top grays as top blues. The stars in gray stones are generally better - meaning each ray fully extends tot he base of the cabochon. Fine stars aren't all that gray stones have going for them. Usually, they are benefited by superior make. Because blue stones tend to be more translucent than gray ones, cutters have to keep more of the original rough to retain asterism and colour. Blue stars are generally cut with sagging bellies while grays are cut with flat ones. Jewellers who do not understand that big bottoms help to preserve stars and colours resent what they think is needless extra weight and expense. The ubiquity of slim, trim Lindes and nice-make natural grays only makes it harder for dealers to explain why so many deep-blue stars are overweight. Forgetting for a minute that unsightly bottom bluk can be hidden in mountings, the deep-blue star sapphire with near-perfect asterism offers consumers one mighty consolation for excess underneath: rarity. Even with one or two legs missing sections, fine blue stones can command up to $1000 per carat in 10 carat sizes. If all the legs are distinct and intact, the price can easily jump to $1500 per carat or more, perhaps as much as $2000 per carat for top-colour 10 carat gray stones with good, well-centred stars, who can blame them? The extra $100 per carat for a more desirable powder blue doesn't seem to present too much hardship either. Madagascar star sapphires from Ankarana frequently display excellent asterism. Our photographs are taken with a fiber optic light above the stone. The stars will look like this in sunlight or under a spotlight. The denim blue color of Madagascar Star Sapphires can be quite even except for the crystal growth lines which prove that the stone is natural. A great stone for a man's or women's ring, natural star sapphires are never clean. It is the silk inside them that accounts for the asterism and clean stars do not exist. In terms of price and quality, blue star sapphires from Madagascar are incomparable in value. Ceylon and Burma both produce limited quantities of blue stars but although they may occasionally be better in quality, their prices are normally substantially higher. The japanese are big buyers of phenomenal stones. Padparadscha Sapphire Padparadscha is easily one of the most abused gem names. Ceylonese dealers use it as a catch-all term for any sapphire that can't be considered a ruby. Because the jewellery industry has not yet adopted any standardised colour measurement system, there is no way to precisely quantify the amount of orange and pink, plus their tonal strength, that constitutes padparadscha colour. The term padparadscha should conjure up images of "luscious lox(salmon) slices". These metaphoric descriptions eliminate from consideration as padparadscha many of the reddish-orange and brownish-orange fancy sapphires often proffered to the public as such. In general, true padparadschas must have the distinctive but delicate pinkish-orange sunset/salmon-flesh colour in just the right balance and intensity. To get that colour, jewellers will probably have to look for stones in excess of 5 carats. Padparadscha require a certain amount of body mass to get its full colour going. Most fine stones are at least 5 to 10 carats or more. Stones also have to be fairly clean. Visible inclusions can dull and flatten even the finest padparadscha colour. Dealers want the vitality as much as proper hue. This translates easily into a minimum of $5000, closer to $10000 per carat for clean, well-cut, true-colour Ceylonese Padparadscha. The "African Padparadschas" from the Umba River region of Tanzania have far more brown and orange than true Ceylonese padparadschas. Although they are beautiful as fancy sapphires, they lack the delicate balance of pink and orange that means so much in padparadscha. Fine padparadscha is far rarer than either fine Kashmir sapphire or Burmese ruby. We're talking about a true Rembrandt among gemstones. "African padparadschas" will cost $2000 to $3000 per carat. The rarest of all colors is the orange-pink of the Padparadscha Sapphire - a Sinhalese (from Sri Lanka) word meaning 'lotus flower'. The main property of Padparadscha sapphire is that it should display the combination of both the colors, orange and pink, and in such a way that it should be difficult to see where one color ends and the other starts. Experts find it difficult to agree on the exact ideal color of Padparadscha sapphire. Padparadschas as a collector item, are hot and snapped up as soon as they appear. Tone and place of origin are crucial factors in determining what is true Padparadscha sapphire. Experts believe that the tone should be light to medium hues of sapphires from Sri Lanka (Ceylon). It has been seen that some sapphires from Tanzania and Madagascar have been sold as Padparadschas, but they had too much of orange-brown to be classified as Padparadscha. The price of the unheated Padparadscha from Sri Lanka ranges from $4,000 to $10,000 per carat. Pink Sapphire - An Amazing case of Colour Blindness When traders buys pink sapphires from Burmese tribesmen, they call it ruby. And they don't take kindly to contradiction. When traders buys pink sapphires from Sri Lankan dealers, they call it padparadscha(an extremely rare pinkish-orange sapphire) - and act offended if you suggest otherwise. Some others took a part in the argument too, insisting that pink sapphire was, at the very least, pale ruby. Even gemmologists contend that calling any pink corundum "sapphire" is a misnomer. After all, pink is in fact a lighter shade of red, and they argue that therefore all such stones should be called ruby. Richard Hughes is one proponent of this argument. As a result, pink sapphire had to fight an uphill struggle to be recognised in its own right. Now the stone is finally beginning to gain a wide following, and is easily the most popular colour of the fancies. Given such trade colour blindness, dealers sit on vast inventories of pink sapphires. The Burmese stones expecially are the centre of of a raging nomenclature controversy regarding the crossover point from pink sapphire to ruby. Pink Sapphire is the second most valuable sapphire. A pure vibrant and vivid pink color makes these gemstones exceptional. It is difficult to decide where it stops being pink sapphire and transits into ruby. The American Gemological Laboratories (AGL) has a grading system that draws a line between pink sapphire and ruby. At that particular point, if the stone is redder, it is ruby; otherwise, it is graded as pink sapphire. Quality and Buying Pink sapphires which command top dollars are from Myanmar, or assumed to be from Myanmar. Some dealers who aren't sure or don't wish to be pinned down on country of origin will describe the stones as Burma-like or as good as Burma. Simply put: Burma means Top Grade. Whether or not an examplary pink sapphire is actually from Burma, such stones always have two traits that go hand in hand: intensity and tone push the stone beyond any association with pastel colour. But colour alone does not justify premium prices for pink sapphire. While not as important as colour, clarity has a big bearing on the value of pink sapphire. One drawback of the Burmese stones is their tendency to be more included than the Sri Lankan variety. The Madagascan variety tend to have this slight secondary yellow-orange cast but it does not have the padparadscha oomph to it. Because pink sapphire is lighter in tone and less saturated in colour than ruby, dealers advise jewellers to buy eye-clean stones. While citing quality factors in pink sapphires, we must make note of brilliance. Although partly a function of clarity, brilliance is also affected by cutting and polishing too. Dealers say that many pink sapphires cut in Sri Lanka are so badly botched that they are deprived of the brilliance they could have. Thankfully, most feel that they can turn to Thailand, which in the last decade has emerged as the world's major sapphire cutting centre for fine cuts. Yellow, Golden and Orange sapphires are relatively less known. To enhance their color, these gemstones are subjected to numerous treatments. Depending on the heat treatment of pale yellow sapphire, the result may be intense yellow, yellow/golden, golden and deep orange-like yellow colors. Natural pale yellow sapphires are heated between 1600 to 1900 degrees centigrade to get better shades. Purple Sapphires are often intense electric purple or plum color. Some have a gray or brown tinge. Exceptional one-carat purple sapphires from Africa and Burma range from $350 to $500 per carat. Larger purples can exceed $1200 per carat. Color Change Sapphires are beautiful, with deep color saturation. Sapphire is one of the gemstones that can change from one color to another, depending on light source. Because of its atomic structure, these sapphires look blue in daylight and seem to go purple or violet under incandescent lights. The color change sapphire with a more dramatic change, is more in demand. The ideal sapphire with this quality has a 100% change with two attractive colors. One should not be able to see two colors under a single light source. More vivid the color change, more valuable is the sapphire. Green Sapphires come from Australia and Thailand. Presence of black/gray secondary colors reduces its value. Pure green sapphires are also found in Africa and greenish blue sapphires come from Burma. Top quality green sapphires are sold for about $250 per carat. White Sapphires were sold at a very low price of $10 per carat, until it was realized that the process of heating changed white sapphires to vibrant orange sapphires. Diffusion process changes these white gems to blue sapphires. With the increase in demand for these gems, the price of white sapphires now ranges from $100 to $300 per carat. Trivia The Logan sapphire is one of the largest blue sapphire gems known. It weighs 423 carats (84.6 g). Lady Diana Spencer's engagement ring from Charles, Prince of Wales was a £30,000 sapphire ring with 14 diamonds. A natural cornflower blue... cornflower. Picture above: A natural "cornflower blue"... cornflower. For sapphires, the choicest colour is the soft velvety blue, approaching the cornflower in shade and exhibiting that colour vividly by artificial as well as by natural light. "Cornflower blue" is one of the most popular colours for sapphires (the other choice colour is a deep "royal blue"), though there is little objective consensus about which shade of blue is the most cornflower or the most desirable. Sapphire is the birthstone associated with September. Treatments The recent appearance of a difficult-to-detect gemstone treatment for corundum, the infamous Beryllium Diffusion, has dealt a heavy blow to the marketability of fancy colour sapphires, in particular orange, yellow, and "padparadscha" sapphires. Green SapphireGreen Sapphire Pictures above: Unheated green sapphire, oval cut 4.56ct. This specimen displays the all too typical "dirty green" colour found in green sapphires. The image on the right shows typical yellow colour zoning. Rough with more serious zoning can be heated with a Beryllium compound to remove the green leaving behind the bright yellow or orange sapphire behind. Geology Sapphire deposits in Sri Lanka, Madagascar, Australia, Antarctica, Kenya and Tanzania are geologically related, as all were connected, billions of years ago, in a super continent called Pangaea. Sapphires, as well as other gemstones, from the same source were deposited throughout this super continent as alluvial gravels. Sri Lanka is known to be closest to this ancient geological source, as the largest sapphires, with better crystallization, are found there. Sapphires in Madagascar and Tanzania are smaller in size, due to the distance they had to travel.