Its crystal structure is hexagonal. Corundum sapphires comes in all color types. Trace mineral content within the crystal gives it color further details on color explained in each specific sapphire type. Corundum is an exceptionally hard crystal structure. The only crystal harder than Corundum sapphire is a diamond cubic crystal structure. Sapphires are a 9 on the Mohs hardness scale. The Mohs scale was developed by Friedrich Mohs in and has been a valuable aid in identifying minerals ever since.
Here are the ten levels of hardness in minerals on the scale:. Whichever mineral scratches the other is harder, if both scratch each other then they are of the same hardness.
The Mohs scale is strictly a relative scale, but that's all anyone needs for basic hardness measurement. In terms of absolute hardness, corundum hardness 9 is 6 times harder than topaz hardness 8.
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. 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. Sapphires come in all ranges of colors from blue to black to colorless and all colors in between. There are no limits to the color tone or saturation of color in a sapphire.
The way in which sapphires have different colors is through the trace mineral content within a sapphire crystal. A blue sapphire will reflect blue light because the crystal has titanium element within the stone. If a sapphire has other trace minerals such as chromium then the stone will be pink in color. If a combination of elements is within the stone, you might have a lime green or a purplish blue sapphire.
A chemically pure sapphire crystal would be colorless. Whatever ingredients nature puts in a sapphire is what special unique color it will show. For this reason, sapphires are extraordinarily unique from one to the next. No two are exactly the same; rare and unusual sapphires are almost irreplaceable, even one that is only 1 or 2 carats in size.
Sapphires come in all sizes. Specimen grade sapphire can come in huge sizes of thousands of carats, but this material has little or no value at all. The Natural Sapphire Company is dedicated to the advancement of knowledge and availability of fine untreated sapphires. In very short detail, an untreated sapphire is one that has been taken from the ground in which it came and faceted.
Nothing at all was done to the stone to alter the natural beauty which only the earth created naturally. These sapphires are exceptionally more rare and valuable. Rarity means that something cannot be replaced easily. When something is rare and a market demand is present, naturally prices will rise. The market for untreated sapphires has continued to rise as more and more consumers become more aware of the treatment of conventional sapphires in the marketplace.
Sapphires of fine quality are in fact very rare. Diamonds, for example, are in almost every type of jewelry, in every jewelry store, and on websites around the world. The world production and use of diamonds proves that diamonds are not at all rare, and in fact are in extraordinary supply.
Prices are held up by a combination of highly inflated profit margins as well as controlled release of supply reserves by the diamond cartels. Sapphires are mined heavily in gem producing countries, by traditional and mechanical methods. Even with heavy mining the rate of return on fine sapphires is exponentially less than the production and availability of most other gem stones. For this reason, specifically natural untreated sapphires are a safe investment for retaining and attaining long term value.
Corundum sapphire comes from all over the world. Commercial sapphires are used in industry for abrasive and cutting purposes. Emory paper is one example of how the hardness of a sapphire crystal is used in everyday industry. Of course the fine gem quality stones are found in very small quantities in very few places.
Most notably are the sapphires from Sri Lanka. For thousands of years fine sapphires have been found in this special place. Most of the sapphires that are found in gem producing locations are worthless; and need to be treated to be marketable.
Good quality sapphires over 2cts are scarce. Pure colors that are free of inclusions are very difficult to produce on a consistent basis. Only a handful of fine stones are produced world wide on a daily basis. The market is far greater than what can be produced and prices continue to rise. This is why natural untreated sapphires are a far better investment when considering making a sizeable stone or jewelry purchase. Blue sapphires are the most popular and sought after type of sapphire.
They have been the prized possessions of emperors, kings, queens and collectors for thousands of years. Still today it is the most well known and in demand colored gemstone. Royalty give sapphires over diamonds as engagement rings because they are known to be far rarer than diamonds. 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. These should be classified differently and priced accordingly. Because of this we do not describe our blue sapphires using this term in most cases. The blue color in a blue sapphire comes from the mineral titanium that is within the crystal. The higher concentrations of titanium in the sapphire, the more color saturation.
Too much color saturation can create a dull or overly dark effect in the blue sapphire which is not desirable and lowers the price of the stone. Most commercial quality sapphires are in fact not blue but black in color. These should not be called blue sapphires as they do not have any blue color or translucency.
These sapphires are very inexpensive. 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. 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 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. At the Natural Sapphire Company we do not believe that origin is a reliable factor worth paying for in sapphires.
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. 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:. 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.
Click here to see examples. The stones were in most cases exceptionally fine quality. 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. 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.
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. 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.
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. 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.
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. 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. 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. 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. 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. As with most things, the more you learn the more comfortable and secure you will feel in making an informed decision when purchasing your sapphire jewelry. Until this time, fine pink sapphires were exceptionally rare and only found in a few locations in Vietnam, Sri Lanka and Burma.
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Learn more. But we do know that the sapphires which are found today were formed around to million years ago. Today the modern location of rubies and sapphires gives us some clues and indications about the place of their formation. The main deposits of high quality sapphires and rubies are found only in a few places, mainly southern Asia and eastern Africa and the islands of Sri Lanka Ceylon and Madagascar.
The answer as to what took place inside the earth to form these gems and then transport them to the surface varies from country to country, but the story remains the same. With advances in science and technology, methods have been created for artificially growing sapphire crystals. The original process was discovered in , and it consisted of alumina powder being added to a oxyhydrogen flame, which is in turn directed downward.
Alumina in this flame is slowly "deposited" in a teardrop shape called a boule. A variety of chemicals can be added throughout this process to create sapphires of multiple hues, as well as red rubies.
While other processes have been discovered since the early s, it is these artificial sapphires that have opened up the use of the stone for technological purposes, including use in panes of glass, and as focusing devices in lasers.
Neal Litherland is an author, blogger and occasional ghostwriter. His experience includes comics, role playing games and a variety of other projects as well. He holds a bachelor's degree in criminal justice from Indiana University, and resides in Northwest Indiana.
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