Brilliant Cut: The Heart of Sparkling Diamonds

Diamonds, as we know them, have a rather symbolic relation with antiquity and grace. Between 15th century and 19th century, nearly 700 diamonds were extracted and cut to fit the crowns and tiaras of kings and queens all over the world. Britain, France and Russian alone consumed nearly 80% of the diamonds. Diamonds are mined from South Africa, Congo, Argentina, Peru, India, Burma and Sri Lanka. 

Diamonds are Brilliant Anyways

Brilliant cut Diamond is the most preferred machine process done on precious stone. The Standard Brilliant Cut gives the most optimal light refraction. The single beam of light passes through the diamond gem and gets refracted in a scintillating manner.

Diamonds are known for their hardness. In fact, they are the hardest known naturally occurring materials. It is one of the popular allotropes of carbon, other being- Graphite. Yes, graphite is the same material used in the pencil lid. Interesting, isn’t it! 

After 17th century, diamonds were cut into many other shapes. Table Cuts Diamond and Fancy Cuts became very popular. In the beginning of the 20th century, Asscher Cut too became very trendy. Even today, gemstones like rubies, sapphires and emeralds are cut like diamonds. Rose Cut, in major polls, ranks as the most preferred diamond shaping trend, especially for the purpose engagement, wedding and anniversaries.

The History of Brilliants 

The first reported instance of tagging a diamond with Brilliant Cut has reference to Italian gem cutters named Vicenzio Peruzzi and Cardinal Jules Mazarin. They are assumed to be the first gem cutters who worked in refining the Point Cuts and came out with something brilliant- Brilliant Cut. 

The history of Brilliants remains shrouded in doubt. It is known that Cardinal Mazarin commissioned twelve largest cut diamonds in France. All of them were listed as the first Brilliants. In 1813, a French lapidary artist and gem collector referred to Vicenzio Peruzzi as the inventor of Brilliants. The historians never acknowledge this notation because of lack of evidence. 

First Guidebook on Brilliant Cuts

The first manual on how to make Brilliant Cuts was published in the year 1750. It was compiled by English diamond dealer David Jeffries who wrote his observations in the Treatise on Diamonds & Pearls. It states that Brilliant Cut diamonds was already available in the market for more than five decades. So, it can be inferred that the English gem collectors were dealing in diamonds from the family since 17th century.

Shapes in Brilliant Cut

Brilliants are cut in Round, Oval and stars. Fancy outlines are also suitable in diamonds from this range. The English gems cut in Brilliant at an angle of 45° made across the crown and the pavilion. They showcase a four-fold symmetry with short lower girdle facets.

Standard Round & Fancy Brilliant

Standard Brilliants are symbols of revolution in gem-cutting technologies. The angles are lowered and reduced table with cutlet facet increases the brilliance of the diamond. Today, Standard Round Brilliants are shaped with Fancy Brilliants resulting in effervescent shapes like ovals, hearts, pears and marquise.

 

Rose Cut: A look at the Pristine Diamond cutting technology

Rose cuts are not new as they are often quoted to be. There have been instances when diamond dealers rate the rose cut as a 20th century phenomena. Breaking the norm, rose cut diamonds were pretty much the regular jewellery items in Antique and Heirloom collections. First rose cut diamond was made in 16th century. This cut continues to win hearts and remains one of the most sought after stones in the modern jewellery sets.

Why Rose Cut diamonds are named so?

The diamonds are cut in the shape resembling the open petals of the rose with spiralling pattern. When cut in the shape of the rose petals, the diamonds have a flat bottom and a larger surface area. This opens the surface to exhibit the brilliance even more emphatically. They feature triangular facets in the multiples of 6 on the tipped crown of the diamond. 

Why rose cuts lost the charm?

Undoubtedly, the rose cut diamond were symbolic representation of the Moughal glory in India. One of the most popular medieval gemstones is the Great Mogul, owned by Shah Jehan. The French traveller and gem collector, Jean Baptiste Tavernier,as one of the most beautiful stones he has ever seen.

Between 18th and 19th century, rose cut diamond lost the position significantly. New machining tools and cutting saws rendered the rose cut diamonds as out of fashion. They were largely replaced by the Brilliant Cuts Diamond. Popularity of Table Cuts and Point Cuts in diamond gems made the floral shaped diamond stones all the more obsolete in 18th century.The cut returned with a bang when the gem collectors tagged this as synonymous with the “engagement” and “romantic” stories.

What are different versions of rose cut?

Rose cuts are made on the diamond in an upside-down manner. The flat base is complemented by the dome-shaped crown converging at the centre of the stone. The different names of the Rose cut are Crowned Rose Cut, Full Holland Cut, Antwerp rose, Dutch Cut and the very popular Antwerp Rose cut diamond is machined in a hexagonal shape.

The Rose Cut Diamonds can be cut into 24 facets and 48 facets (called Double Dutch Rose). If you observe closely, the "Briolette Cut diamond" is actually a modified twofold Dutch Rose cut which has half of its hemisphere elongated against the other hemispherical half.

Another prominent variety of the cut is the Senaille Cut which has notable unsymmetrical facet.

Rose Cut Diamond Solitaire: The Magic

Considered as a regale cut, Rose Cut is used extensively in diamond solitaire, re-introduced with brilliant clarity and pristine lustre. The open mouth cut allowed the light to pass through the crystal freely with no hindrance in the setting.

Almost all diamonds can be cut into Rose. The most prominent factors to determine the feasibility of cutting a diamond into Rose are width and depth of the stone. Symmetry and crystal alignment are secondary factors that lapidary artists look for before going ahead with Rose Cut.

Colour changing Gemstones: The Mystery Decoded

There are exclusive gemstones named specifically as per the colour they reveal. For instance, Turquoise, aquamarine gemstone, opal, lapis gemstone and many more are only a handful of an exhaustive list. And then, there are others that have an effervescent optical characteristic of changing colours depending on the angle you view them, or on the way light falls on them.For example, Alexandrite runs a beaming green shade in daylight and mysteriously transforms into richly blue under fluorescent light. 

If that is not enough, the same stone displays a majestic play of orange and red colour when exposed to incandescent light.

How distinct is colour change phenomenon in gemstones?

Colour change is a well-recognised optical phenomenon that occurs in a gemstone when exposed to different wavelength of light. This optical property is observed in sapphires and garnets too, but it is exclusively called “Alexandrite Effect”. 

What is Alexandrite?

A type of chrysoberyl, Alexandrite is an orthorhombic gemstone named after the Tsar of Russian, Alexander II (1818-1881). Discovered for the first time in the Urals near River Tokovaya in 1834, the gemstone gained immense popularity only after master gemstone George Frederick Kunz produced some of the most magical platinum and diamond ensemble featuring Alexandrite. 

What contributes to the Play of Colour?

The chemical composition complemented by the crystalline structure and its double refraction index of 0.009 gives the stone its majestic optical brilliance. Just like its optical phenomenon, the crystal itself so very rare in the nature. Alexandrite is not a regular chrysoberyl. In addition to iron and titanium oxides, the gemstone also contains traces of chromium. Some minor traces of vanadium and gallium are also present but they are considered as impurities, rather than featuring as colouring agents.

Due to the presence of so many ions, Alexandrite reveals a show of colour ranging from green to yellow, brownish red to purple, yellow green to bluish green.

The most genuine form of gemstones 

Alexandrite is rarest gemstone to make it to the collector’s list. They are mined from Sri Lanka, India, Madagascar, Zimbabwe, Burma, Tanzania and Brazil. Synthetic Alexandrites are yet to be produced with satisfying results. They remain untouched by the heat treatments and dyeing agents that mark the markets for sapphire and rubies.

A true gemstone bearing the tag of Alexandrite always exhibits two optical phenomena: Cat’s eye gemstone or chatoyancy and change of colour.

Cut and Clarity

Alexandrite is blessed with clear lustre and rarely has any inclusions. It’s the inclusions in sparing numbers that give the gemstone its chatoyancy property. Often cut in mixed cuts, aristocrats prefer uncut Alexandrite owing to the rarity and save weight. They are mostly available in cut form weighing less than one carat.

However, some world-famous Alexandrite stones are actually way heavier than standards. For example, the 17.08 carat Whitney or the 43 Carat Gem or 66-Carat Gem… they all are big and magnificent.

Perfect engagement gifts revered by the lovers all over the world- The Alexandrite Russian rings set on platinum…

Roman Love: Sizzling Garnet Varieties

Garnet bracelets are one of the world’s oldest recognised forms of gemstone jewellery. The Romans were known to adorn the rings and crowns adorned with garnets gemstones of different sizes.  They continue to be as impressive as they used to be in the 15th century. 

Garnets look like Pomegranate grains! 

Yes, they do resemble the fruity grains. And that is why they are named from Latin word “Garanatus” that translates to “like seeds of pomegranate”. Small garnets are brighter in shade than the bigger ones. If you have difficulty analysing the authenticity of the garnet, get it tested under a refractometer. There are many varieties of garnets. Some of the popular varieties are:

 

  • Pyrope
  • Almandine 
  • Grossular hessonite/ tsavorite
  • Uvarovite
  • Andradite 
  • Rhodolite
  • Spessartine 

 

Here are some less common, but very precious garnets available in the market sparingly.

 

  • Goldmanite
  • Morimotoite
  • Katoite
  • Hibschite
  • Kimzeyite
  • Schorlomite
  • Majorite
  • Calderite
  • Hydro-grossular
  • Knorringite
  • Kimberlites

 

World of synthetic garnets

Garnet is one of the easily synthesised gemstones in laboratories.  Apart from silica, calcium and magnesium, garnets crystals can be impregnated with ions of Germanium, Gallium, Aluminium, Vanadium and Iron. 

Very similar to zirconium, garnets too have their own series of synthetic gemstone members. Yttrium aluminium garnet- YAG, is one of the most popular and commercially accepted garnets to have made it big in the market. Other significantly popular synthetic garnets are Yttrium iron garnet- YIG, and Gadolinium gallium garnet- GGG. All synthetic garnet beads are coated with a film of magnetic substrate to replicate the magneto-optical properties as seen in the real gems.

So, how to identify a real garnet?

Physical testing for hardness, colour, magnetic properties and abrasive nature are popular methods used to separate original garnets from the synthetic ones.

Colours of garnet

Garnets used in modern day jewellery exhibit myriad colours like red, orange, yellow, green, purple, brown, blue, black, pink and burgundy. Some garnets are pale and colourless as well which can be coloured after heat treatment. 

Darker the colour of the garnet, older is the age of the gemstone. Depending on the diffusion, garnets can have shallow colouring as well as core colouring. 

Discovered in 1990s, there is a special family of garnet called Blue pyrope–spessartine garnets. They exhibit multiple colour hues when observed from different angles. The colour changes from shades of green to purple, depending on the diurnal temperature and natural slight intensity.

Hardness 

Garnets is one of the hardest naturally available material on the planet. The synthetic garnets have hardness measured in Mohs scale. They could be anywhere between 6.5 and 7.8.

Magnetic Properties 

Easily the most authentic method to detect original garnets, magnetic susceptibility to neodymium magnet is a common feature among end members of the series.

But hey! Like all gemstones, garnets too can be faked and forged with impressive adulation. That is why there are certain restrictive trade regulations to keep only original garnets in the market. Find and assess gemstone certification that is tagged on every garnet. 

 

Aquamarine: Finding the gems that will give you rewards

Aquamarine is an iconic gem belonging to the same family that also features Green Emerald. Officially ranked as the birthstone for those born in March, Aquamarine gemstone has a glassy lustre and a sea-water hue. But are you aware that there are thousands of duplicate gemstone items that flood the market each year, and remain untraced. So how should one find and buy authentic Aquamarine.

Here’s what you should do.

Research about famous Aquamarine

Aquamarines are found as large stones that need cutting and polishing. Most of the naturally mined gems are either opaque or too dull to be used for profitable application. You must do a little research on the world famous Aquamarines. 

Dom Pedro:  Officially, Dom Pedro is the largest single piece cut-gem Aquamarine and falls in the category of rarest of rare natural items ever mined from the Earth’s crust. Named after the first two Brazilian emperors, Dom Pedro now stands as 14 inches in the shape of obelisk. It was cut from its 23.25 inches glory by gem artist Bernd Munsteiner.

The Hirsch: It is a 109.02 carat gemstone featuring an emerald-cut. It was one of the first non-treated gemstone to be exhibited all over the world. It was set in 18k gold bracket and diamonds by French Emperor Louis XV. 

The Schlumberger Bow: Currently ownedby the Field Museumof Natural History- Chicago, “The Schlumberger Bow” is set in platinum and gold pin along with diamonds. It is a 148.5 carat aquamarine designed for Tiffany. It was first exhibited in the year 1893.

Roosevelt Aquamarine: Gifted to First Lady of USA, Mrs. Eleanor Roosevelt in 1935, the gemstone is one of the largest naturally extracted aquamarines to be ever mined. It weighs 1847 carat. It was cut from a 1.3 kilogram stone of which a single 835 carat aquamarine was gifted to the Maharaja of Kapurthala.

The leading suppliers of aquamarine gemstone beads are Australia, China, India, Kenya, Madagascar, Mozambique, Namibia, Nigeria, Pakistan, Zambia and Zimbabwe. Radiant gems still come from Santa Maria mines in Brazil. So it is not all about the volume, but also about the position Brazil commands in Aquamarine gem market.

How to identify the originality

# Aquamarine Colour

Aquamarine can exhibit multiple shades of blue, variedly or consistently. It all depends on the amount of chromium and iron ions in the crystal lattice. The popular shades are light blue, deep blue,blue-green and green-blue. The cost of aquamarines is decided on the basis of the shade saturation and consistency. 

# Aquamarine Clarity/Lustre

Deep blue shades are costlier, only if they have a lustrous, crystal clear appearance. Some gems however can have rods running parallel seen like veins and inclusions. Aquamarine can show multiple optical characteristics like chatoyancy and asterism. 

# Aquamarine Cut and Shape

Aquamarine gems are cut in cabochon, but faceted cuts also hold significant place in collections. They are perfect for emerald cuts and square cuts. Emerald step-cut and Fancy Cuts are hard to manage, but they are popular among aristocrats as they were before World War II.

Opalescence: The Glorified History of Milky Stones

Searching for real opals? You should be familiar with the characteristic optical features that a natural, untreated opal exhibits. To check the authenticity of the opal, get it under a Turbidity meter. All opals exhibit an optical phenomenon derived from their own primary name- opalescence. It is defined as the milky and turbid appearance in opal. 

Opals: The Magic of Milky White

Often referred to as the stone from the Cosmos, opal is a Sanskrit word- Uppal meaning “precious milky stone”. It is a gemstone largely constituted of hydrated silicon di oxide. It is an amorphous stone and is extracted largely from the Southern Hemisphere. In fact, it is actually the National Gemstone of Australia.

The various forms of opal are:

1. Precious Opal

2. Fire Opal

3. Potch Opal

4. Girasol Opal

5. Blue Opal Gemstone, also called Peruvian opal

Opals actually exhibit both Play of Colour as well as Opalescence. 

How opalescence occurs in the gemstone?

Opalescence is confined largely to the blue spectrum during reflection of short wavelength light rays. It is because of this phenomenon that a gemstone appears turbid with a shiny blue surface. Another reason, it appears blue is due to the significantly high traces of water, which could be as much as 21% of the silica crystal volume. 

The spaces where water is present hinder the passage of light, making the gemstone look milky. Through these spaces, no diffraction occurs. The internal scattering around the water traces render the opal its characteristic opalescence.

Opals that made History

Opalescence can occur along with white, colourless, yellow, red, grey, black and fiery shades of red and blue as well. Diffraction causes flashes of Play of Colour. Intensity of opalescence decides the brilliance and clarity of the gemstone, and hence commands the price. The red opal beads as well as blue opal beads are extensively used in jewellery. 

Opals in flat cabochon glorify the opalescence in the most beautiful way. The most popular opal gemstones in the history of mankind are:

Sun God Opal:

A 16th century gemstone, carved from mines in Mexico. It is a 35 carat Aztec-era stone with a singular quality. It is a dazzling item showcasing opalescence and play of colours brilliantly.

Dark Jubilee Opal:

A thrilling example of Australian opal deposits, this 314.8 carat gemstone was mined from Coober Pedy. 

The Olympic Australis

Named after the Olympic Games in Melbourne, this is one of the purest mega-carat gemstone ever mined. Valued at $2,500,000 (Australian Dollars), it is a massive 17,000 carat opal exhibited all over the world.

The Butterfly Stone

Also named as the Red Admiral, it is a unique gemstone exhibiting opalescence at only certain angles. It resembles the red English butterflies and hence the name.

Empress of Australia

Rightly named, this gemstone was mined in 1915. It is referred to as ‘Kaleidoscope Queen’ and ‘Tartan Queen’. It weighed 500 carats in its initial days of glory.

Other prominent opals owned by museums and individual collectors are Pride of Australia, The Flame Queen, The Black Prince and Halley’s Comet.

 

A look into Heat Treatments of Rubies & Sapphire Gemstone

Rubies and sapphire gemstone available in the market are available in two forms. One category would be heat treated with additives, and another would be those without additives. It is obvious that though heat treatment is done to improve the colour of the gemstones, adding extraneous stuff to the crystal structure actually means that there has been physical distortion with the original gemstone. In short, gemstone that has been heat treated with additives is what you should stay away from.

Let us review how heat treatments with and without additives work, and why they are important in gem studies.

Heat Treatments without additives

Natural gemstones command higher price than those manufactured artificially. Natural stones may not be perfect in terms of their brilliance and crystalline structure, but their origin is all that matters. Gems created in labs have lower value primarily because they may not give the same healing benefits that they are known for. 

Heat treated rubies beads and sapphires are common, and they are respected for their consistency and suitability in different applications. They are heated under specific temperatures, glazed in condition that is free from impurities of any kind. Depending on the amount of oxides and the colour-bearing properties, rubies and sapphires exhibit the same beauty as their natural counterparts.

It is important to note that sapphires and rubies are heat treated using different agents. Heat treatment for sapphire gems is carried out in reducing process, while rubies are heat treated in an oxidizing environment. 

Heat Treatment with additives

The heat treatment process using additives is not illegal, but it affects the commercial viability of a gemstone. All gems have to be necessarily subjected to inspection by leading gem quality testing labs, and this is where additives are named.

The most popular gemstone treatment processes using additives for rubies and sapphire are:

Lead Filling

Also called fracture filling, this process is utilised to cover up the fissures and cracks. Rubies and sapphires with dull and rough appearance are infused with lead to produce high refractive indices. It can be used for opaque gems as well, which after lead filling result in brilliant transparent or translucent/ milky stones. 

Cheap rubies are available in the market, and they are more often than not, lead filled. Moreover, this additive process is actually reversible. Lead filling for gemstone has been rendered as hazardous, as lead is a carcinogen.

Recrystallization

In order to enhance the transparency and improve the refractive index, rubies and sapphires are made to undergo recrystallization. The first known synthetic ruby was actually produced using this process. Geneva Ruby in 1886 made headlines, but it turned out to be a reconstructed gem. Same process is used to produce emeralds. 

Beryllium Treatment 

An accidental discovery led to the commercialization of this process. Between 2000 and 2006, the market was full of richly coloured padparadscha sapphires. Lab testing proved that they were actually orange sapphires, diffused with beryllium ions. Even in natural stones, sapphires have been found to contain significant amount of beryllium impurities. 

Is it safe to wear irradiated Gemstones

It is true that even the most naturally obtained gemstones have to be exposed to some kind of radiation to make them look super cool. This process is called Irradiation and it is done by bombarding a stream of gamma rays at the crystal structure of the gemstone. It indeed makes the gems radioactive. Let us find out if the irradiated gemstones are anyway harmful to the consumers.

Which stones are irradiated?

Topaz is the most commonly irradiated gemstone. Blue topaz gemstone is one of the rarest gems, and is often manufactured synthetically. Nearly 28 million carats (which is roughly 6000 kilograms) of topaz are irradiated each year, globally. USA leads the source, followed by Germany, Poland and Thailand.

Other gemstones usually found in their irradiated states are yellow, blue, green and pink diamond gemstone. Quartz and amethyst beads are also exposed to radiation at some point of time in their life cycle. Goshenite, golden beryl and Heliodor are popular beryls available exclusively in irradiated states. Black pearls extracted after 1970, are either dyed or are irradiated to look stunning. 

So with so many precious gemstones exposed to radiation, it is obvious that consumers need to know to what extent they are susceptible to any hazard.

Is there any way gemstones are regulated in the market?

Yes. All irradiated gemstones have to be necessarily given a certificate from the regulating agencies in the respective countries. All gem producing and gem treatment nations have strict regulations to monitor the radioactivity levels in the irradiated gemstones, whether natural or artificial.

Here are some precious and semi-precious gemstones that have been ranked among radioactive items. 

 

  • Adularia 
  • Afghanite
  • Ajoite
  • Amazonite
  • Betafite
  • Boleite
  • Charoite
  • Eudialyte
  • Francevillite
  • Londonite
  • Polycrase
  • Sugilite
  • Thorite
  • Titanite

 

Despite their radioactive state, they are deemed safe for use on a daily basis.

Who testifies for irradiated gemstones in the market?

Irradiation is a very commercial process for manufacturing gemstones. The finished items have to be approved by Federal Trade Commission. Other prominent professional organizations are American Gem Trade Association, The World Jewellery Confederation and International Coloured Gemstone Association.

How to tell ifthe gemstone is irradiated?

A gemstone seller can’t sell irradiated items without necessary certification. One of the most recognised certification comes from United States Nuclear Regulatory Commission. Physically, it is very difficult for even the experts to tell whether the gem has been irradiated naturally, or in a reactor or in an accelerator. The certificate, followed by a testing with survey meter is the only way any lay person can adjudge the gemstones as irradiated or not.

Are they safe for daily wear?

Yes. The irradiated gemstones belong to the family of birthstones, and the customer is required to wear it daily for effective healing and metaphysical benefits. Irradiated gemstones don’t radiate back. The effect of irradiation is exhibited through the change in colour due to the distortion in the crystal structure. The change in colour is permanent and so is the non-radioactive state of the gemstones.

Hence, irradiated gemstones are absolutely hazard-free.

 

A look at Prominent Diamond Cuts since 13th Century

Going back to the 12th century, we will find the first instances of how diamond cutting became a trade of respectable position in the society. As royal families and noblemen began to showcase their pomp and glory through silk and gemstones, diamond slowly began to raise its head as one of the most precious items of collection in the treasury. The first diamonds were cut in manner that resembles the modern Point Cut. We are not talking about the trend in the year 1970, but in 1287. 

Here are some truly antiquated diamond cuts that still retain their place in modern day gem cutting trends.

Natural Points

Diamonds that crystallised in octahedral and do-decahedral crystal lattices are left uncut. These are natural crystals and have remained so for millennia. Before America and Australia were discovered and conquered, the only source of diamonds was the Indian sub-continent. A Point Cut diamond is actually a misnomer as there are no tools involved in the machining. 

Pyramidal Point Cut

Grinding became a regular gem cutting and polishing technique, especially after 15th century. Big diamonds were smoothened and polished without taking away their size. Out of multiple girdle profiles, a lapidary artist would choose the one with the largest contour in diamonds. Diamonds have always carried the charm of bestowing magical and healing effects on the person wearing them. Keeping them untouched and natural was no longer a fashionable trend. Hence, slight polishing using Pyramidal Point Cuts made at shallow planes compared to natural points became more popular. 

The Burgundian Point Cut

Burgundian Point Cut is preferred for diamonds with dodecahedral crystals structure. This crystal lattice has many irregularities and requires intensive polishing. The dodecahedron crystal is aligned in a way that the four faces seem as if rising upwards. 

Table Cuts

A remarkable refreshing cutting pattern, diamonds were first cut in Table Cut using diamond dust itself! The first Table Cut diamond was shaped like alphabet “M”. It was probably the first engagement ring ever gifted. Not to forget, before Rose Cut diamond became the symbol of love and romance, Table Cuts were the fashionable items.

Old Mine Cushion Cuts

Europeans dug out new sources of diamond gemstone. Amazon and Sahara became the diamond potboilers for traders. The new cutting models for vibrant diamonds beads meant embracing an indigenous gem shaping technique. Old Mine Cushion Cut took birth in the 18th century bearing an uncanny resemblance to what we know as Modern Brilliant Cut. They gave birth to the aristocratic cuts like marquise cut/navette cut.

Old Mine Cushion Cut was produced using bruting machine powered by steam, and later motors. English Round Cuts were born from the improvements in diamond bruting machines, some of which produced 58 flawless facets in a single diamond gemstone!

Asscher Cut 

Named after the world renowned gem cutters, the Asscher Brothers of Holland (they cut the world’s largest diamond- Cullinan), this is very similar to what we call Square Emeralds bearing large facets, small table and an elongated crown.

The World of Diffusion Sapphire Gemstone

Sapphires can be artificially treated in labs in many ways. One of the most prolific technologies to produce these gemstones is lattice diffusion. So let us do a quick review on the lattice diffusion sapphires.

What is lattice diffusion after all?

Lattice diffusion is a commercial gemstone treatment process that involves use of heat and chemical agents to diffuse the ingredients into a gemstone so that it will change colours as per requirement. The best part of using this technology is that gemstones of any colour can be produced. Sapphire gemstone showcasing myriad colours like vibrant red, fiery purple, electrifying blue, silky yellow and pitch dark blacks are produced using diffusion through the crystal structure.

In some cases, sapphire beads are treated with lattice diffusion that can have shallow embeds of colours superficially exhibited on the surface. In others, the colours can penetrate deep into the very core. It all depends on the conditions and impurities already present in the crystal structure that interact with each other randomly during diffusion.

Is lattice diffusion for sapphire legal?

Heat treatment is a legal and accepted technique used on sapphires and rubies. Lattice diffusion however, require regulation from top gem laboratories and trade organizations as far as production and selling are concerned. Lattice diffusion, in no way, adds monetary value to the gemstone. It only improves the brilliance and clarity with a more consistent appearance. 

It is legal, and is very different from the process of dyeing and stabilizing. The molecules added to the crystal structure can’t be detected even under the most powerful microscope. Hence, a gemstone dealer has to necessarily produce a certificate labelling the stone with lattice diffusion.

Types of diffusion methods 

 

Apart from lattice diffusion, certain gemstones are also treated using Surface Diffusion and Pipe or Channel Diffusion.

Surface diffusion

It is the addition of natural colouring elements like iron, copper, titanium and chromium to the shallow surface of a gemstone during heat treatment. 

It is sued largely on corundum and silica-based gemstones after cutting is done.  

The colour penetration is usually less than 30%.

It is done at melting point of the element so that it diffuses evenly into the crystal up to a depth of 1 millimetre. 

Surface diffusion is done for blue sapphire beads and rubies. Colour obtained on a gemstone using the surface diffusion could be lost due to re-polishing, scratching or resetting.

Channel Diffusion

Also called as pipe diffusion, this heat treatment technique is applicable to feldspar and Labradorite gemstones. It is done using copper as the diffusing element. The diffusion occurs along the channels and can be easily detected under microscope. 

Identification of surface and channel diffusion sapphires is done by studying the bands and zones running parallel to the crystal facet.

Unlike the gemstones that are heat treated using chemical dyes and fillers, those produced using lattice diffusion are relatively sturdy and long lasting. They cost a little less than other varieties but exhibit the same brilliance and clarity. Moreover, they are easier to machine and cut.