May 22, 2022

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Natural sapphire stone guide

Sapphire is one of the four most precious gemstones (which are diamond, ruby, emerald, and … sapphire) and certainly the best known with diamond. Blue sapphire is by far the colored gemstone the most used in jewelry.

For most people, sapphire means blue sapphire as this is the most famous type of sapphire stone. In fact, there are many varieties of sapphire gemstone that can be of any color, from white (or colorless) to green.

Sapphire is actually a variety of corundum with traces of other chemical elements that give it its color. It is characterized by a hardness of 9 on the Mohs scale, just after moissanite which has a hardness of 9.5, and below diamond which has a hardness of 10.

View of a blue raw sapphire on the left and a pear cut blue sapphire on the right

Blue sapphire is the most used of the precious stones in jewelry while people are generally not aware of the different types of sapphire colors, or quality criteria of sapphire stones.

This article is a complete guide to help you discover what corundum is, what are the different types of sapphires and their colors as well as to help you know the quality criteria of sapphire and have an idea of its price.

TABLE OF CONTENT

  1. What is natural Sapphire?
  2. What is sapphire color range?
  3. Padparadscha Sapphire
  4. Star Sapphire: Black, Blue and Others
  5. What is Ceylon sapphire?
  6. Sapphire Stone Price
  7. Raw Sapphire Stone
  8. Natural sapphire mining in the world
  9. Lab created Sapphires (synthetic versus natural sapphires)
  10. Natural sapphire treatments
  11. Sapphire Birthstone
  12. Natural Sapphire Market Data
  13. Sapphire Alternatives in Jewelry

1. Chemical Composition of Natural Sapphire

Sapphire is a mineral, called corundum, which is aluminum oxide (Al2O3) whose crystalline structure has traces of other chemical elements giving it its crystal color. These elements can be iron (Fe), titanium (T), chromium (Cr), vanadium (V), or magnesium (Mg).

Cristaline structure of corundum, which can be sapphire or ruby

Above, you can see the cristaline structure of corundum wihout any trace of chemincal elements determining its color

Because of these chemical elements, corundum can take on any color, with the particularity of being called ruby when this color is red and sapphire in all other cases (blue sapphire and fancy sapphire)

Indeed, ruby is colored corundum, just like sapphire. What defines the ruby is its red color which can be more or less intense and when a ruby is only weakly tempted, then it will be called a pink sapphire.

Corundum color comparison between ruby and pink sapphire

Comparison between a ruby and pink sapphire, with the same chemical composition, only the concentration of chromium differs from both gemsones samples

It is the presence of chromium in the crystalline structure of corundum that gives it a hue ranging from pink (then called pink sapphire) to deep red, it is then called ruby pigeon blood.

The concentration of impurities necessary for the appearance of color varies according to the chemical elements. While at least 1% chromium is needed in the corundum structure to obtain a deep red ruby, only 0.01% iron and titanium are needed to give it a blue hue.

2. What is Sapphire Stone Color Range? 

Sapphire is mostly known for being a deep blue precious stone, while it can take on many different hues, including blue, pink, green, yellow, orange, black and white with numerous intensities and shades of color depending on the type and concentration of chemical elements found within its structure.

sapphire color range

Examples of sapphires of different colors, ranging from blue to green through yellow and orange and colorless sapphire or pink sapphire. Sapphires with a large range of colors are used for rainbow ring making as shown on the rigth

Blue Sapphire

Blue sapphire is a corundum that owes its hue to chemical impurities in the form of iron and titanium oxides. Its perceived color depends on its hue, the intensity of the hue, the brightness of the blue and the tone (light or dark) and also the shades of color that are visible depending on the orientation of the stone. For blue sapphire, its shades generally range from purple to green.

Its price also depends on its purity, visible to the eye, but we will come back to this in the next chapter about sapphire price.blue sapphire ring with cushion cut sapphire

 Solitaire blue sapphire ring with cushion cut, made through our custom ring service

Blue Sapphire are the most look after on the jewelry market and the most expensive sapphires are all blue. The most expensive sapphire stones are the one with pure blue hue and a vivid saturation.

Yellow or Orange Sapphire

It is the presence of iron and iron alone in the corumdum that gives sapphire its yellow or orange hue, the presence of a single another element changing its color from yellow to ther color. For this kind of clear hue, the purity of the stone is all the more important, since any imperfection is very visible to the naked eye.

natural yellow sapphire ring natural sapphire ring with yellow solitaire sapphire

 yellow gold ring set with a natural yellow sapphire cushion cut

Yellow sapphire cushion cut ring, this ring of our collection is adapted here with a nice yellow sapphire of 8 mm

Given its hardness and pronounced yellow hue, yellow sapphire is an excellent alternative to yellow diamonds, this latter being much more affordable than a diamond when lookng for a stone with a pronounced hue.

Pink Sapphire 

As explained above, pink sapphire is a corundum mineral containing traces of chromium and having a hue too weak to be called ruby. Pink sapphire is also an excellent alternative to pink diamonds, which are, for the average person, quite expensive, whereas pink sapphire is quite affordable, in comparison.

large natural pink sapphire ring with gold shank and diamonds

Pink sapphire gemstone and a ring set with a pink sapphire giving you an idea of the visual rendering of the gemstone well highlighted 

The value of pink sapphire rise when the pink color gets deeper (increase in chromium concentration). Pink sapphire is a good subtitute to pink diamoands, close in hue and so much cheaper.

White Sapphire

White sapphire is a corundum crystal without impurities, it is rare because most of the time, during its formation, its crystals are “polluted” by other chemical elements.

It has often been used in jewelry as substitute to diamonds, which is less common today given the development of synthetic diamonds and zirconium oxide which is so economical.

 white sapphire stone with brillant cut

Top and bottom view of a colorless white sapphire whose color is noticeable but whose luminous reflections have nothing to do with those of a diamond

As you can see on the picture, white sapphire is not as white as G or H diamond and does not show the brightness or fire you can see with diamonds.

Green Sapphire

As with yellow sapphire, it is the presence of iron oxide that gives it its green hue. Green sapphire is almost unknown to the general public and is not much in demand in jewelry. It is however a beautiful and very resistant stone and really economical for a precious fancy gemstone.

Natural green sapphire gemstone with pear cut

Green sapphire competes with emerald, another more fragile but much more fascinating gemstone, and it can also be a substitude with les precious gemstones such as tsavorite and peridot, which are much more economical.

Color Change Sapphire

Color change sapphires are natural sapphires which color change depending on the incident light. Commonly, they show one color on the day light and another one when exposed to artificial light. 

This phenomenon is quite rare and is called the “alexandrite effect” for the name of the Alexandrite gemstone showing the same color change.

Such type of sapphire can be blue at daylight and become purple with artificial light or be green at day light and become pink/violet with artificial light. Color change sapphire above two different lights showing the color change of the gemstone

Example of color change sapphire with blue hue under natural ilght and becoming purple under incandescent light (source)

Such color change sapphire are mined in different areas of the world such as Madagascar, Tanzania and Sri Lanka (ex Ceylon).

These color change sapphires must not be confused with natural bi-color sapphires that show different hues in a single stone.

samples of natural bicolor sapphires

These samples of bicolor sapphires are all natural (source GIA)

3. Padparadscha Sapphire 

Although little known to the general public, Padparadscha sapphire is certainly the rarest of all natural sapphires and also one of the most expensive. It is characterized by its unique orange-pink color and historically comes from mines located in Sri Lanka. Today, such sapphires are also found in mines in Madagascar and Tanzania, which is best known for its production of tanzanite stones

Its name derives from the Sinhalese word Padma radschen which means “lotus flower”, the color of this stone is surprisingly similar to that of the flower, as you can see below.

Color comparison of Padparadscha sapphire with the lotus flower

Visual showing a lotus flower with its vibrant colors as well as a cut padparadscha sapphire and a rough padparadscha sapphire allowing you to see the colors of each

Padparadscha sapphires are the most expensive fancy sapphires after natural blue sapphires. Nowadays such Padparadscha sapphire color can be obtained through beryllium diffusion treatment (see sapphire treatments chapter here below).

The color of Padparadscha sapphire is so unique that even experts do not agree at all about the color definition of these sapphires.”It is GIA’s opinion that this color range should be limited to light to medium tones of pinkish orange to orange-pink hues.”

This rare sapphire can be found in those countries: Sri Lanka, Madagascar, Malawi, Tanzania, Myanmar.

4. Star Sapphire color range

Star sapphires are colored corundum with inclusions of rutile (TiO2) in the shape of needles showing a six-rayed star pattern when looked at day light (note that the star will disapear to the eye with artificial light). This star effect appears white over the fancy colored sapphire that is cut in cabochon to give the best effect to this phenomenon.

Star sapphire exist in all fancy sapphire colors, the most famous are blue and black star sapphires. When a red corundum shows a star effect, it is called Star ruby.

This star like effect is called asterism.

While black sapphire is little known and little coveted in jewelry in the form of cut stones, black star sapphires are much more famous and used in jewlery. The white star overing on the black sapphire gives a stunning effect on any jewelry set with this type of sapphire.

Black star sapphire with cabochon cut

Cabochon-cut black sapphire with astherism phenomenon also know as black star sapphire

Below, you can see a blue star sapphire cabochon set on a ring. To be valuable, the star sapphire must show a clean and clear white star with no defects. The more valuable star sapphires are blue star sapphire, then pink star sapphire and black star sapphire are the least expensive ones.

Blue star sapphire set on white gold ring

Example of a blue star sapphire cabochon cut set on a ring 

In theory, this asterism phenomenon could appear in any colored corundum, while I have never heard about star Padparascha sapphire, it would be more expensive than a pink star sapphire.The largest blue sapphire in the world are blue star sapphires, the largest one being The Star of Adam with a weight of 1404,5 carats that was mined in Sri Lanka in August 2015.

5. What is Ceylon Sapphire?

“Ceylon is not just the oldest source of sapphire, with continuous production over 2000 years, but also has produced most of the large fine sapphires ever seen, with top stones ranging up to 500+ carats” say the sapphire expert Richard W. Hughes (source).

Ceylon sapphire are also known as Sri Lanka Sapphires as this small island on the shore of India was known as Ceylon up to 1972 when if changed its name. to Sri Lanka.

Among all the mines and countries producing sapphires, there are some that stand out for the quality of their sapphires and the history that surrounds them.

Ceylon sapphires are part of these mythical sapphires given their worldwide fame. They were the most coveted gemstones by the European crowned heads before the diamond became the most fashionable gemstone during the 40s, following the advertising campaigns of the mining company DeBeers.

To give you an idea, Ceylon was mentioned by Ptolemy for its gems 1800 years ago. Marco Polo also mentions it in his writings in the 13th century. It is estimated today that about 25% of the island’s surface is rich in gems.

Sri Lanka is a small island in southeast India that was called Ceylon until 1972. The name of the sapphires from this island has stuck to the sapphires from this island which is still considered one of the main sources of the most beautiful sapphires in the world.

Ceylon, Sri Lanka position on the world map

Traditionally, when we talk about Ceylon sapphire, we are talking about blue sapphires, however it should be noted that the island produces sapphires of all colors, including Padparadscha sapphire we mentioned earlier.

The following map shows the location of the main deposits and mining sites of sapphires on the island.

Ceylon, Sri Lanka is the source of the most beautiful and most colorful sapphires

Map of Ceylon (Sri Lanka), source map

As you can see, the occurrence of sapphires is most important in the Highlands, which are the areas shown in light green on the map and the blue areas show the main known sapphire deposits.

Ceylon blue sapphires are the best known of all the sapphires on the island, they offer indeed an exceptional hue, a blue color with reflections of mauve characteristic of their origin.

Ceylon sapphire ring

Example of a Ceylon sapphire stone set on a gold ring

6. Sapphire Stone Price 

In conventional jewelry, depending on the quality of sapphires and market demand for them, sapphire stone cost vary from 200 dollars to 3500 dollars per carat for blue sapphires.

Setting the value to a sapphire stone is particulary difficult as its price will vary depending a lot on its color, its purity and mining origin. Its price will also be impacted by the market demand, the mining activity , the political situation in the countries producer of sapphires and the politicial agreement or bans that can exist.

The most expensive sapphires are the blue sapphires which can reach prices up to $242 000 dollars per carat as it was the case during the auction of a blue Kashmir Sapphire in 2015 at Sotheby.

The single most important criteria to set the value to a sapphire is its color. That’s why a sapphire color chart is used to classify the hue of blue sapphires, the vividness of the color is also important so as the clarity (presence of inclusions) of the cristal.

Below is a blue sapphire color chart showing the vast range of blue hue taken by blue sapphires.

blue sapphire color chart used to set sapphire price

All the criteria affecting a sapphire value are listed here:

  • Hue, color vividness and tone
  • Clarity, size and cut
  • Geographical origin
  • Treated or untreated

Other criteria as local mining capacity, fashion for some kind of sapphire or banishment from some importator countries can also have an impact on price that is difficult to evaluate.

Nowadays, a lot of enfasis is made about the stone mine origin creating a hype on some specific mining regions of the world, this origin becoming more imortant than the sapphire stone quality and beauty.

As Richard W. Hughes from Lotus Gemology says “stones with Kashmir walking papers from major labs can fetch as much as ten times the price of an identical stone from Madagascar. Many Burmese sapphires are indistinguishable from sapphires from Sri Lanka, even with the most sophisticated testing. In many cases, labs cannot accurately separate blue sapphires from Sri Lanka and Burma. Additionally, it is extremely difficult to separate some Sri Lankan stones from those of Kashmir and Madagascar.”

He also explains how easy it is to fake the procedency of a sapphire to rise its price upward: 

“As of 2020, Madagascar’s production of fine blues is probably greater than both Sri Lanka and Burma combined. Most of the buying in Madagascar is done by Sri Lankan buyers and as the stones are taken to Sri Lanka for cutting and treatment, many of the blues now sold in Sri Lanka are actually from Madagascar. This misrepresentation of Madagascar origin is one of the major causes of disagreement between labs and their customers. That said, as the quality of Madagascar sapphire becomes better recognized, we are starting to see market prices move towards those from Ceylon”. (source)

About the sapphire’s price per carat evolution, we can note these auctions showing  a high increase in demand for top qualiity sapphire gems since 2005:

“On December 1, 2009, a private bidder paid $2.396 million for a 16.65 ct Kashmir sapphire at the Christie’s Magnificent Jewels auction in Hong Kong—at almost $144,000 per carat. In the four years prior to that sale, auction prices for top Kashmir sapphires ranged from $39,000 to $135,000 per carat.” (source)

7. Raw Sapphire Stone

Raw sapphire stones are precious corundum cristals in their primitive form as the nature made them in the harsh conditions of the underground. Gemquality are found in bedrock rivers or mining in their rough primal form before being cut to reach the jewelry market.

The most common raw sapphires are found in basalt or marble.

Raw sapphires that do not reach gemquality are used as fantasy pendants or by collectioners as ornemental pieces.

raw sapphire in different colors, yellow and blue

 On the left, a raw bicolorsapphire, on the right a blue sapphire rough, both are ornemental pieces

As you can see, the shape of the sapphire rough is following a geometrical pattern that is due to the hexagonbal structure of the corumdum cristal. When they are expulsed to the surface by volcanos or water worn, sapphire rough can brake and take a very different shape (barrel shape), like a common rock, but showing its incredible color. 

Did you know?

Sapphire is formed under heat but has to cool slowly to allow the formation of the mineral lattice. The slower it cools, the bigger the sapphire stone can be.

sapphire rough stones of different types and colors

Having such a common shape can madke them difficult to find in the middle of thousand of other small rocks, as you can sse in this video:

8. Natural Sapphire Mining in the World

While many people wonder about the provenance of the stones in their jewelry and the working conditions of the workers who mine the deposits, it is worthwhile to present the current state of sapphire mining.

Understanding the formation of sapphires

A bit like a diamond, sapphire is formed in the bowels of the Earth, at the level of the lithosphere, where the pressure and temperature are sufficient to create the crystal of aluminum oxide from the mother rock composed of aluminum and silicon Al2SIO5 and other chemical elements that will give its color to corundum.

The presence of mother rock and the pressure are not sufficient, it is necessary moreover a source of heat (the magma) which will allow the formation of the crystal of corundum

And it is still the magma that will subsequently expel the raw sapphires thus formed underground to the surface of the earth’s crust.

According to scientists, natural sapphire is formed at a depth of about 60 kilometers, under a pressure of 20,000 bars and a temperature of 1100°C.

Once forced out by the magma, sapphires are found in alluvial deposits due to the erosion of magmatic rocks by natural elements.

The sapphire mines

Although sapphire crystallizes in hard rocks, such as basalt or marble, it is in alluvial deposits that it is most easily and profitably mined.

Kashmir sapphires are mined in the rock at an altitude of more than 5000 meters. I recommend you to see this excellent documentary  by Patrick Voillot on Kashmir sapphires:

Most of the time, sapphire mines are exploited with very few means, by digging the ground between 1 and 6 meters deep in order to search and sort the sapphires by washing the sediments that surround them.

The means of exploitation of the miners are proportional to the means available to the country according to its degree of development. The majority of sapphire mining is located in Southeast Asia and Africa, where it is mainly done by hand.

Here is a map showing all the sapphire mining sites for the jewelry market, the first three being the most important ones:

world map of sapphire mining sites

World map showing all the sapphire mining sites (source)

As you can see, there is a lot of unknown mines that produce very little sapphires or low grade sapphires (like USA and France). The main production sites both in quality and quantity are Madagascar, Sri Lanka and Tanzania.

How much sapphire is mined every year? 

This is a very hard question to answer as mines’ production vary year to year, local climate events can affect the mine’s site access or local political change affect the ability to export sapphires.

Moreover, as much of sapphire production occurs in third world countries, smuggling is very common and just a fraction of  the sapphires extrated get registred by the governments.

If that was not enough, poor quality gems that had been extracted years ago are now treated with modern techniques allowing those stones to reach the jewelry market.

Here are some official sapphire mining data from local governments: 

  • Jammu and Kashmir mining regions in India reported mining 15,000 kg of gemquality sapphire between 1963 and 1998, 9 kg from 1998 to 2001, and 21 kg between 2002 and 2007— with colors ranging from near-colorless to dark blue.
  • Of the 150 top price-per-carat sapphires sold at the major auctions between 1979 and 2008, 121 were described as Kashmir.
  • Production of blue sapphires, the principal object of Sri Lanka’s branding efforts, declined 66.9% between 2006 and 2007, from 472,961 carats to 156,486 carats, while the price per carat rose 18.9%, according to the report, and per-carat prices for untreated goods soared.
  • In 1987 Thailand became one of the world’s largest sources of blue sapphire. Production began to decline in the mid-1990s, with less than 200 kg recovered annually from 1995 through 2005, a tiny fraction of the world total. 
  • Today, an estimated one million Thais make their living from the gemstone industry through cutting, trading, and treating (“Thailand government waives VAT. . . ,” 2009). Approximately 70% of the world’s sapphires and 90% of its rubies pass though Thailand. Most are treated and cut in Chanthaburi.Figures published by the Gem and Jewelry Institute of Thailand (2009) indicate that polished gemstone exports in 2008 totaled approximately $254.89 million, of which sapphire represented 46.7% and ruby 40.62%. Although the export value of cut gemstones increased nearly 50% between 2007 and 2008, imports of rough declined 13% ($22.9 million to $19 million) for the same period.
  •  Australia’s sapphire production declined by some 60%, from an estimated 13,000 to 5,500 kg from 1995 to 2005. In the 1980s, Australia was the source for about 70% of the world’s sapphires, mostly from New South Wales (source).
  • Vietnam’s sapphire production soared from an estimated 40 kg in 1996 to 1,700 kg two years later, but by 2001 production was down to 70 kg.
  • Malawi sapphire production tends toward pink, red, and purple, in sizes yielding a maximum of 2–3 ct gemstones (Rankin, 2002). Some 4–5 kg of material have been mined annually in recent years (ICA 2006 World Gemstone Mining Report, 2006). More recently, approximately 50–100 kg of yellow and blue sapphires have been produced, though the blue sapphires are routinely heated.
  • Madagascar‘s sapphire deposit proved lucrative, with some 1,200 kg exported to Thailand annually from 94 to 97 and a number of 15–20 ct stones cut . Because a high percentage of the sapphires produced were smuggled out of Madagascar, production statistics tend to be incomplete and contradictory. One report said that by 2005, Madagascar was responsible for an estimated 50% of the world’s sapphires (Tilghman et al., 2007). It is supposed  that 50 kg of sapphire were smuggled to Thailand each week, supported by a World Bank estimate that the country saw less than 5% of its potential revenues from sapphire exports (“Getting stoned,” 2005).
  • In the USA, The American Gem Corp. undertook largescale mining efforts at Rock Creek between 1994 and 1996, producing more than four million carats of gem-quality rough (800 kg)—and, for a brief period, making Montana one of the world’s largest sources of sapphire. This production has thus far yielded more than one million faceted gems (Kane, 2003).

Working conditions in sapphire mines

If in countries like USA, Canada and Australia, mechanical means, culture and labor laws allow the exploitation of sapphire in good conditions, it is quite different in Africa and South East Asia where machines are scarse, the culture and the standard of living are very different from the Western world criteria and the access to the mining sites is so easy that there are a lot of illegal exploitations, as it is the case in Madagascar, today one of the countries producing the most sapphires in the world

9. Lab Created Sapphires 

Sapphire has so many incredible physical characteristics that it si used in many industrial applications, well beyond the sole jewelry industry. Sapphire has a wide optical transmission band, it is much stronger than glass, highly resistant to scratching and melt at a very high temperature (higher than many metals at 2030°C).

Nowadays, white or colored sapphire are used for watches’ crystals, high pressure or vaccuum chambers, semiconductors with integreated circuits SOS type, armored vehicles, lasers and prosthesis implants in medicine. The sapphires used for such applications are man-made to reach the requirement in size, weight and purity of the industry.

In 1902, the French Chemist August Verneuil succeeded to create the first synthetic ruby and in 1909 he created the first lab created blue sapphire. The Verneuil process was the first industrial process for producing synthetic gemtones to be a commercial success.

Another method: Czochralski process has been developped in 1916 by polish chemist Jan Czochralski, since then this process has been modernized and allow the production of dozens or hundreds of kilos of sapphir cristal at once.

These techniques have overflown on the sapphire jewelry industry and lab created sapphires are now available for making jewelry.  

Let’s be clear, lab created sapphires are sapphires but man made, they have the same mineral structure and are identical to natural sapphires, and very often, they need a gemmologist to determine if they are natural or lab created. Lab created sapphires are much cheaper than natural sapphires.

This is the reason why, everywhere in the world it is a requisite to stipulate the man made origin of any synthetic sapphire. Laboratories of gemmology everywhere in the world offer their expertise to certificate your sapphire is natural or synthetic.

Here is an example of microscopic clues that use gemmologists to determine the type of sapphire, natural or lab created. 

microscopic view of natural sapphire versus lab created blue sapphire

Photo showing the microscopic clues indicating the laboratory origin of synthetic  sapphires (source)

Some inclusions can also help identify a lab-made gem. For example, curved striae are found only in synthetic sapphires and rubies, never natural ones. See this article on inclusions of synthetic gemstones for more information.

10. Natural Sapphire Treatments

If you plan to buy an expensive or big sapphire stone for your jewelry, it is a necessary requisite to be aware of the sapphires treatments to choose your stone.

Sapphire treatments are common since hundred of years, as the GIA laboratory explains it: 

“Historically, sapphires and rubies have been coated with substances to enhance their color, or dipped in oil to improve apparent transparency. Such practices—as applied to a variety of gems—were described by Pliny the Second two millennia ago. More-sophisticated treatments—particularly high-temperature, atmosphere-controlled heating of corundum—are now commonplace”

Some treatments are common, others are accepted in the jewelry industry as long as they are disclosed to the buyer. Commonly, treatments that improve the stone without affecting much its price are well accepted while treatments that sharply raise the sapphire stone price have to be disclosed.

Here are the different treatments of sapphire stone used in the insudtry:

  1. Low heat treatment
  2. High heat diffusion
  3. Lead-Glass Filling also known as Fracture filling

Low Heat Treament

This is the most common and oldest treatment of all. 

As corrundum needs chemical elements and heat to form and show its color, sometimes the natural pocess of sapphire formation is not completed by lack of heat to reveal the strongest hue the stone could show.

This low heat treatment consists in finishing the job of mother nature by heating the sapphire stone up to 800°C during several hours, which imporve its clarity and blue hue of the stone. This method is also used to improve ruby color.

This kind of treatment is very common and almost all the sapphire stones on the market are heat treated.

High Heat Diffusion Treatment

This is a new treatment that has been used for a few decades only. It consists in heating the sapphire at high temperature (more than 1000°C) in presence of other chemical elements to allow the supperficial diffusion of those elements in the mineral structure (lattice).

Usually, this method is used with colorless sapphire with diffusion of Titanium to give the corrundum the blue hue of blue sapphire.

Since the years 2000, it has also been used for Beryllium diffusion in colorless corrundum to create Padparadscha sapphires, as GIA laboratory mentions: 

“In late 2001, large amounts of pinkish orange “padparadscha” sapphires—represented as natural color—began to appear on the market. While prominent gemologists soon suspected a form of diffusion, there was no understanding at the time about what elements might cause the “padparadscha” and orangy colors on a consistent basis. Thorough investigation proved that a diffusion treatment was indeed being used, and that beryllium was the element being diffused at extremely high temperatures (Emmett et al., 2003). The sudden appearance of these treated sapphires (figure 21), combined with their clandestine release into the marketplace, caught gem dealers and gemological laboratories by surprise (Henricus, 2002). These stones also caused substantial disruption in the gem community, at least temporarily, because the treatment was difficult to detect”

Lead-Glass Fracture Filling

As corrundum is naturally formed under heat and pressure, its lattice shows fractures and voids that can be seen as defects and lower the value of the stone. Fracture filling treatment consist in filling thoses fractures with other components that will mask those defects, improving the aspect of the stone and its value. It is illegal not to disclose such a treatment.

Treatment detection 

Today, it is easy to detect such treatments, “however, it often requires advanced instrumentation such as laser ablation–inductively coupled plasma–mass spectrometry to establish the presence of beryllium” (source GIA)

Also, detecting low heat treatment is not always as easy, as Richard W. Hughes explains it: 

“There are a number of sapphire sources around the world where sapphire is found associated with alkali basalts. These include Australia, Cambodia, Cameroon, China, Ethiopia, Laos, Madagascar (far north), Nigeria, Rwanda, Thailand and Vietnam. In such stones, the sapphires formed within the earth, but were brought to the surface by volcanic eruptions. During these volcanic events, the already-formed crystals underwent a natural heating process. The result is that basalt-related sapphires often show features associated with sapphires that have undergone artificial heat treatment. Due to this fact, it is often impossible for labs to know if a basalt-related stone has been artificially heat treated.” (source)

Laboratory sapphires are easily recognizable because for a very affordable price, their hue is perfect, without variations and without any defect, details that can easily be noticed with the eye or with a magnifying glass on a natural sapphire.

If you want a natural stone that has not undergone any treatment, then you will need a certificate from a laboratory that has analyzed your stone and you need to have the budget for such a stone.

Yogo Sapphire, natural untreated Sapphire

While not really of consequence in the world sapphire market, there is strong demand for Montana sapphire in the US. It comes in two distinctive flavors, Yogo and non-Yogo (meaning Rock Creek/Gem Mountain, Missouri River and Dry Cottonwood Creek).

Yogo sapphires have been mined on and off since the late 19th century. With beautiful blue to lilac colors, high clarity and no color zoning, the only thing that has stopped them from being world class is the size. Most crystals are flat and it is a rare stone that can cut a one-carat piece. Two-carat stones are extraordinarily rare. Yogo sapphires fetch prices in the US far above what would be paid in the rest of the world.

Stones from the other Montana mines come in fancy colors and blues tend to be a bit grayish. Rock Creek/Gem Mountain produces prodigious quantities, but virtually all require heat treatment. (source)

11. Sapphire Birthstone : Meaning and Benefits

Sapphire is the birthstone of September for people with astrological sign Virgo. This concerns people born between the 23 of August and the 22nd of September. The tradition of birthstones is as old as the Jewish history. The modern birthstone calendar was formalized by Tiffany and Co in 1870 and publlished in the form of a poem you can read entierely here, which extract for the birthstone of september is:

September birthstone poem:

A maiden born when September leaves
Are rustling in September’s breeze,
A sapphire on her brow should bind
`Twill cure diseases of the mind

Not only sapphire is a precious stone nowadays, but it has been precious for centuries for having a strong spiritual meanning and healing benefits.

Sapphire stone has been known for more than 2000 years. It has been the stone of Maharadja, Kings, Princes and religious leaders. The most recent example of this, is the blue sapphire engagement ring Prince Charles of England offered to Lady Diana in 1981, untill her death in 1997. It was the property of the Royal family of England and Prince William offered the same sapphire ring to Kate Middleton in 2010.

Sapphire is a symbol of sincerity, loyalty, wisdom and nobility. Back in the antiquity, nobles believed the sapphire stone protected them from harm and jealousy.

12. Natural Sapphire Market Data

Here is a presentation of data about the sapphire world market to get a better understanding of volumes and value of sapphires sold every year. Over the past 35 years, sapphires went from high-priced goods to arguably the world’s most widely sold colored gemstones, accounting for approximately one-third of all global colored stone sales by value.

It is safe to conclude that up to and through the 1970s, the market for faceted blue sapphire and ruby was small relative to the quantities in the jewelry industry today, simply because supplies were limited primarily to the low percentage of facetable goods (typically less than 5%) that came from the mines in salable colors.

Recently, two market research studies have shed light on sales of colored stones in general—and ruby and sapphire in particular—at wholesale and retail. They found—not surprisingly—that corundum represents the largest single share of the colored stone market. One study, published in 2009 in Dubai, reported that the world retail market (of which the U.S. accounted for 60%) for all “precious” gemstones was approximately $80 billion: $69.7 billion for diamonds and $10.3 billion for colored stones and pearls. Of the latter amount, ruby and sapphire accounted for 30%, while emerald was 12%. The remaining 58% comprised all other gems, including pearls (BUZ Consulting, 2009).

$3,09 billions worth of sapphires and rubies were sold in 2009.

The second study, commissioned by True North Gems, pegged the pipeline (retail sales and inventory) for ruby at $2.1 billion and sapphire at $800 million ($58 million of which was pink sapphire), for a total similar to the approximately $3 billion cited in the Dubai study. The same source noted that emerald sales totaled $1.4 billion. The sapphire share is low in comparison to that of ruby because of the large quantities of low-quality and diffusion-treated sapphire in the market (Smith, 2009). 

The 1980s marked the point at which the treatment of previously worthless material suddenly resulted in the widespread availability of appealing blue sapphires.

The majority of sapphire stones sold in 2009 are low-quality and treated stones.

Today, an estimated one million Thais make their living from the gemstone industry through cutting, trading, and treating (“Thailand government waives VAT. . . ,” 2009). Approximately 70% of the world’s sapphires and 90% of its rubies pass through Thailand. Most are treated and cut in Chanthaburi, where the weekend gem markets still draw thousands of buyers and sellers (figure 11), and are then exported through Bangkok .Figures published by the Gem and Jewelry Institute of Thailand (2009) indicate that polished gemstone exports in 2008 totaled approximately $254.89 million, of which sapphire represented 46.7% and ruby 40.62%. Although the export value of cut gemstones increased nearly 50% between 2007 and 2008, imports of rough declined 13% ($22.9 million to $19 million) for the same period.

In 2009, 70% of the world’s sapphires pass through Thailand.

Madagascar’s Sapphire deposits proved lucrative, with some 1,200 kg exported to Thailand annually from 94 to 97 and a number of 15–20 ct stones cut. Because a high percentage of the sapphires produced were smuggled out of Madagascar, production statistics tend to be incomplete and contradictory. One report said that by 2005, Madagascar was responsible for an estimated 50% of the world’s sapphires (Tilghman et al., 2007). This may be explained by a claim that 50 kg of sapphire were smuggled to Thailand each week, supported by a World Bank estimate that the country saw less than 5% of its potential revenues from sapphire exports (“Getting stoned,” 2005).

Madgascar has been a huge source of sapphires in the 90s and 2000s years with a lot of material smuggled our to Thailand and difficult to track.

Here is the prospect about the future of sapphire world market:

The Dubai study (prepared before the fall 2008 onset of the global economic crisis) predicted that sales of colored stones would grow an average of 6.1% annually around the world. However, that report and other sources (Emmett, 2007; Shor, 2007c) listed a number of challenges that could hamper growth in retail demand for colored stones, including corundum:

• There are no universally accepted grading standards, which makes colored stones more difficult to describe and appraise than diamonds.

• Apart from tanzanite and several varieties of pearls, there are no coordinated large-scale marketing efforts, such as those that have helped spur diamond, gold, and platinum jewelry sales.

Supplies can be unpredictable. Colored stone deposits tend to be relatively small and sporadically distributed, and thus many have a short life span.

• The perception of the financial community is that the colored stone industry is a “Wild West” environment, with few laws and extremely fragmented markets.

• The lack of documented information about the colored stone industry deters banks and other financial institutions from offering credit lines.

• Sales of colored stone jewelry are more closely tied to fashion trends than other forms of jewelry and thus are more volatile.

• Treatments remain an issue, and debates continue over “acceptable” and “unacceptable” treatments.

• As with diamonds and other gemstones, however, world events, local conflicts, and political upheavals have affected supplies and, possibly, consumer attitudes toward ruby and sapphire.

(Source GIA)

13. Sapphire Versus Other gemstones in Jewelry

As sapphire can take a wide spectrum of colors, there is a lot of other gemstones that can be confused with or replace sapphire stones on your jewelry.

White sapphire versus Moissanite

Moissanite is a silicon carbide (SiC) that is almost never found in nature while white sapphire is a natural aluminium oxyde (Al2O3) that is naturally made.

Moissanite set on your jewelry is always a lab-createde stone.

Moissanite’s hardness on Mohs scale is 9,25/9,5 while white sapphire hardness is 9, so Moissanite is a little bit harder than sapphire. So Moissanite will scratch your sapphire.

In terms of appearance, a natural white sapphire will show imperfections and inclusions while the moissanite will be almost perfect, being man-made. The refraction index and fire dispersion of the moissanite is much better than those of white sapphire and is similar to those of diamond.

This is the reason why moissanite is used to replace diamonds over white sapphire, and why moissanite is more expensive than white sapphire as the market demand is higher.

White sapphire versus Cubic Zirconia

Cubic Zirconia is a Zirconium dioxide (ZrO2) with a Mohs scale hardness of 8/8,5 which is less than white sapphire. It means your white sapphire will scratch your cubic zirconia stone.

Cubic zirconia has also a better refraction index than white sapphire which makes it a very good imitation of diamond at an unbeatable price, much better than white sapphire.

White sapphire versus white topaz

Topaz is a silicate mineral (Al2SiO4) with a Mohs scale hardness of 8 whitch is less than white sapphire.Topaz will be scratched by any sapphire stone.

Topaz has a refraction index inferior to the refraction index of white sapphire, which makes it less luminous than sapphire. Also, white topaz is cheaper than white sapphire.

 

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