What to consider before purchasing a Natural Blue Sapphire
Recently I had a client request help in sourcing a fairly expensive blue sapphire. The first question he had was in regards to what part of the world the stone would be sourced from, and what types of verification would be supplied. His concern was very common and well justified, as the price of a blue sapphire is often reflected by the region in which it was sourced, also known as it's origin. In my opinion, the origin should not be as important as the sheer beauty of the stone. Making your blue sapphire purchase through an informed dealer you trust is going to be your best bet. Once you are able to examine several stones, and compare and contrast what does and does not appeal to you, you will be in a better position to select the right stone. To help you better understand why it is so important, let us take a closer look closer at the sapphire and the market.
What is a sapphire?
The scientific name of sapphire crystal is called Corundum. A sapphire (corundum) is an aluminum oxide mineral (Al2O3 and Its crystal structure is hexagonal. Trace mineral content within the crystal gives it color. Blue Corundum is called Blue Sapphire; Pink Corundum is called Pink Sapphire, etc. Sapphires have an exceptionally hard crystal structure, ranking 9 on Mohs Hardness scale. To put this into perspective, the only crystal which is harder is a diamond! Whichever mineral scratches the other is harder, if both scratch each other then they are of the same hardness. Hardness directly corresponds with how durable a stone is. Have you ever heard the expression, " A diamond is forever" - it was coined because diamonds are extremely durable.
Refractive Index & Identification
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. Sapphires can easily be identified using a refractive index test. A sapphires color will have no influence on it's refractive index reading. All sapphire colors will have the same refractive index reading, which for Corundum is 1.75 - 1.76
What gives a Sapphire it's Color?
As we discussed, trace mineral content within the crystals, give them their color. Blue sapphires contain trace elements of titanium, and pink sapphires contain trace minerals of chromium. There are no limits as to what combination of trace elements can be present in the crystals, and therefore all sapphires have unique colors. For this reason, no two sapphires are exactly the same.
Sapphires come from many places around the world but only a few locations produce the fine quality that command high prices in the jewelry stores. The most beautiful sapphires come from the same countries as they have for thousands of years.
Sri Lanka (Ceylon) & Madagascar
The quantity and quality of blue sapphires coming from Sri Lanka is only rivaled by new deposits found in Madagascar. The sapphires from Madagascar and Sri Lanka are almost indistinguishable as Color tone and internal crystal characteristics of these sapphires are almost identical. The prices for blue sapphires from both countries are similar.
Burma is a sovereign state located in Southeast Asia. Its official name is the Republic of the Union of Myanmar, often informally shortened to "Myanmar". Burma produces arguably the very best quality sapphires. Usually Burmese sapphires are a rich dark royal blue color. Usually the largest sapphires are found here and they cost 50% - 100% more than sapphires from Madagascar or Ceylon.
“Kashmir” sapphires were in most cases exceptionally fine quality found in a very remote mountainous region of India in the late 1800’s. 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, therefore supply of these stones is very scarce.
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.
Grading a sapphire on origin is not a reliable science.Even the best gem laboratories in the world have a large margin of error when testing for origin. The reason is simple; sapphires 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. Paying a premium for “origin” is often proven an unwarranted expense as there is no guarantee that the stone is in fact from that location in which is specified. There have in fact been instances where grading labs have identified the exact same sapphire as being from two different regions.
Why are sapphires treated?
The most common form of treatment for a sapphire is Heat treatment which involves heating the stone at extremely high temperatures to "enhance" it's color and clarity. Most people are unaware that almost all sapphires are treated. Prices for treated sapphires fluctuate and are not very consistent so it is impossible to put reliable value on them. Either a sapphire is treated or it is not and this should be the first consideration in determining value. Below you can see the drastic changes in appearance after heat treatment.
The price of a blue sapphire is dependent on whether it is treated or untreated, size (carat weight) light reflection, color tone, saturation, the clarity of the stone. Loose sapphires are priced by the quality of the stone multiplied by the carat (ct.) weight. The finer the material the higher the price 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. Sapphires, and all gemstones for that matter, are not like diamonds in that they are not regulated and a standardized pricing system is not in place, so a buyer should always do thorough research before purchasing an expensive sapphire. A good jeweler or gemologist who is familiar with the quality attributes of blue sapphires can help you feel more comfortable in making an informed decision when purchasing your sapphire jewelry.