Hardness
Corundum is an exceptionally hard crystal structure. The only crystal harder than Corundum (sapphire) is a diamond (cubic crystal structure).
Whichever mineral scratches the other is harder, if both scratch each other then they are of the same hardness.
. Because it isn''t made for that kind of precision, the Mohs scale uses half-numbers for in-between hardness. Sapphire is an incredibly hard and durable crystal.Refractive Index
One way to identify a crystal species is by taking a refractive index test. Refractive index is the reading of how a crystal separates the spectrum of light. Each crystal structure will separate light differently and this is one reliable method to identify a crystal structure.
A refractive index test on a pink, blue, yellow or green sapphire will give the same refractive index reading. The wide range of colors of sapphires will have no influence on refractive index readings. The test only identifies the crystal, not the coloration of the crystal as viewed by the human eye.
Blues
Blue sapphires come in various hues from very light pale baby blue to a very rich royal blue. A sapphire that is black should not be called a blue sapphire; this is a commercial quality stone. If a sapphire is to be called blue” it must not have more than 15% secondary color tones within the stone such as yellow, green or purple. Sapphires that have secondary colors that are significant should be classified “greenish-blue” or “purplish-blue” “violet” etc. These are not “blue sapphires”, rather they are “unique” or sometimes called “fancy colors”. These should be classified differently and priced accordingly.
A note on the term “Cornflower Blue”: This is a term used by many people in the jewelry and gem trade. It is our opinion that there is no definite way of defining “cornflower blue” as a color. The reason being, there are many very different color tones that people refer to as “cornflower blue.” Some people believe this color is a darker richer tone of blue; while others believe it is a lighter softer blue tone. Because of this we do not describe our blue sapphires using this term in most cases. Too often it is used as a “buzz word” to increase the impression of a stones quality.
Origins of Sapphires
Sapphires come from many places around the world but few locations produce fine qualities. The most beautiful sapphires come from the same countries as they have for thousands of years. Only a few new deposits have been discovered in recent times.
Sri Lanka (Ceylon) & Madagascar
The most notable producer of fine blue sapphires is Sri Lanka or “Ceylon” as referred to within the trade (Ceylon was the former name of the country. It has only recently changed to “Sri Lanka” since gaining independence from the British).
The quantity and quality of blue sapphires coming from Sri Lanka is only rivaled by new deposits found in Madagascar. The sapphires from Madagascar are in many cases almost indistinguishable against sapphires from Sri Lanka. Color tone and internal crystal characteristics of Madagascar and Ceylon sapphires are almost identical in most cases. The prices for blue sapphires from both countries are similar.
Burma and Origins
Burma (now called Myanmar since gaining independence from the British) is another long time producing country of fine blue sapphires. Usually Burmese sapphires are described as royal blue, typically on the darker side of royal blue. Many gemologists, retailers, auctioneers, and other stone houses will talk very highly of Burmese sapphires being the very best quality sapphires; we do not necessarily agree that this is true and fair. Each sapphire should be graded by its visual appearance for sheer beauty. Burma does produce excellent stones, usually in smaller quantities but larger sizes. Burmese sapphires will almost always cost 50% - 100% more than a sapphire from Madagascar or Ceylon.
At the Natural Sapphire Company we do not believe that origin is a reliable factor worth paying for in sapphires. We recommend primarily grading a stone based on its inherent natural beauty and in almost all cases to put little value on “origin”. With our extensive experience specializing in natural untreated sapphires we urge that pure natural beauty remain the absolute priority.
Grading a sapphire o norigin is not a reliable science. Our experience using the best gem laboratories in the world for origin certification has resulted in an approximate 50% margin of error. Reasons for error are simple; sapphires from most prominent locations all have characteristics internally that cross over with each other from one “origin” to the next.
Inclusion types associated with Madagascar also are seen in Kashmir sapphires. Ceylon sapphires very often have identical inclusion types found in Burmese sapphires. Madagascar and Sri Lanka have almost all the same characteristics. Our experience with so many incorrect origin identifications from the laboratories have resulted in our company only buying stones that are:
Paying a premium for “origin” is often proven an unwarranted expense. We do state the origin of our sapphires based on where we purchase the material, but it is not a guarantee that the stone is in fact from that location.
To prove that reputable gem labs have a very hard time determining origin, we will be adding examples of contradicting results on the same sapphire.
Kashmir
“Kashmir” sapphires are talked about in almost a mythical way these days. Kashmir sapphires were found in a very remote mountainous region of India in the late 1800’s. The stones were in most cases exceptionally fine quality. The color tone term “cornflower blue” was coined from these stones. The term is generally described as “velvety” or “sleepy” being that the color is very soothing and appealing. The deposit was exhausted by the 1920’s and there have been no new finds in the Kashmir area.
For this reason the prices for Kashmir sapphires have been wildly valued. Prices can be 10 times the cost of a comparable blue sapphire from another country.
Problems with Kashmir Sapphire Today
Stones from Madagascar are very often described to look like Kashmir quality. Many stones are thought to be graded incorrectly by the laboratories as Kashmir sapphires, but actually come from Madagascar or even Sri Lanka. For this reason we do not recommend the extraordinary prices that “Certified Kashmir” demands.
Early 19th century jewelry and Kashmir sapphires played a large role together, and these stones are very beautiful indeed. We highly recommend Madagascar sapphires, as they can look identical to proven Kashmir sapphires. Of course true Kashmir sapphires exist and are documented in famous jewelry. But when a fine velvety Kashmir and fine velvety Madagascar sapphire are put side by side it can be very difficult to determine which is finer.
Other producing countries of blue sapphires such as Thailand, Tanzania, Australia, Montana (USA), and Cambodia do produce sizeable quantities.
They are generally viable for commercial jewelry use only. They do produce fine rare sapphires on occasion that can be expensive, but this is not reliable production. Most blue sapphires coming from these locations normally have secondary color tones and need to be treated to be saleable.
Treatments, Value & Details
First, natural untreated blue sapphires are in a class of their own. Either a sapphire is treated or it is not. This is the first consideration in determining value. There are so many types of treatments and alterations of sapphires that it is almost impossible to list them all. Therefore it is now a basic matter of either the sapphire being 100% untreated or not. Prices for treated sapphires fluctuate and are not very consistent so it is impossible to put reliable value on them (Please refer to our section on Treatments of Sapphires to see the extraordinary differences between natural and treated sapphires).
The second consideration in evaluating a blue sapphire is sheer beauty. In most cases beauty is agreeable from one person to the next. Something stunningly attractive will always hold value and be in demand. A slight preference in color tone is normal from one person to the next. Normally these personal taste preferences should not be seen as better or worse. It is possible to lean towards a blue sapphire that is slightly darker in color or lighter in color depending on individual appeal. One should not look at “the highest priced” as the defining quality factor. You must love what you buy and it must have value.
Uniform color, light reflection and clarity are all important in grading quality and price of sapphires. Details on shape, cutting style and origin are purely valued by personal taste and should not be labeled “better or worse” when considering a sapphire.
Prices of blue sapphires are dependant on whether they are treated or untreated, their color tone, saturation, the clarity of the sapphire, and size. Loose sapphires are priced by the quality of the stone multiplied by the carat (ct.) weight. Just as you would purchase fine fruit at a higher price per pound over lower quality fruit, sapphires are priced the same. The finer the material the more it will cost per carat. As a person becomes more and more familiar with quality attributes of blue sapphires they develop an accurate “price per ct” trading range of the material. A seasoned shopper of apples in a grocery store can tell you the high and low end range of apples by the pound, as can a seasoned shopper and buyer in sapphires.
Small light blue sapphires (approx. 1ct) can be as little as a few hundred per ct, while a 1ct exceptionally fine blue sapphire can be more then $2000 per ct. Price ranges for larger stones have a comparable price spread, so there is a very large price range for similar sized stones with very different color, clarity and cutting properties. It is important that all of these determining factors are understandable so that pricing makes sense.
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