Gemstone Treatments
- Coating. This treatment is achieved by applying a thin film to the surface of a gem partially or completely in order to...
- Dyeing. Dyeing refers to one of the oldest treatments recorded. The treatment involves the introduction of a coloring...
- Clarity enhancement/Fracture filling. Clarity enhancement/Fracture filling refers to the filling of surface...
What is a coating on a gemstone?
COATING (Enhancement code C) Some gems are coated with a thin film using similar techniques to those used on computer chips. The most commonly known versions are the “Aqua Aura”, “Mystic” or “Azotic” coatings which give the gem an iridescent look.
What are treated gemstones?
Any special care instructions for these treated gems are also provided. – a chemical used to alter / reduce a component of, or the entire color, of a porous gem. Some gemstones are bleached and then dyed, a form of “combination treatment.” 1. The most commonly encountered bleached gems include:
What are the benefits of heat treatments for gemstones?
Gemstone heat treatments can increase the beauty and value of many rough pieces. Learn how to conduct the most common procedures safely. The AGTA has proposed the use of gemstone treatment codes to promote disclosure and a common language for these procedures. Learn what these codes…
Are coated gemstones ethical?
Regardless of their longevity, any ethical practice requires full disclosure. Most commonly coated gem materials are quartz, beryl and topaz, which display quite obvious color modifications and unnatural iridescence. Dyeing refers to one of the oldest treatments recorded.
What does coated mean on a gemstone?
A gemstone which is covered by an artificially applied transparent material or mineral to enhance its colour and appearance, is known as a coated gemstone. The technique is often used with coloured Topaz to create Mystic Topaz, and colourless Quartz is turned into Mystic Quartz using the same process.
What is the difference between treated and untreated gemstones?
Untreated gemstones are those that are not altered or enhanced in any way. They remain in the same form as when they were extracted from the earth. These gemstones remain in their original form and only get polished and cut to be used as jewelry accessories.
How do you tell if a gemstone has been heat-treated?
Heat treatment is a very risky process as many gems have inclusions that expand at a different rate and cause stress fractures, which then becomes an identifying characteristic of heated gems, particularly sapphire and ruby which can display halos around inclusions within the gem.
Do heat-treated gems fade?
The color of a heat-treated sapphire will remain permanent and will not change or fade unless the stone undergoes a secondary treatment. This is the reason why heat treatment on sapphires is accepted by most retailers.
What gemstones are not treated?
AR: Some gems are not usually treated, like spinel, garnet and tourmaline.
How can you tell if a sapphire is treated?
The study of inclusions in sapphires is a sure way to detect if a sapphire has been treated. Heating sapphires at extreme temperatures change the internal characteristics so much that it is quite easy for a trained gemologist to determine if the sapphire has been heated.
What does heat treated mean in gemstones?
Heat Treatment is a gemstone's exposure to high temperatures that alters the color and increases the clarity. Specifically, heating is used to lighten, darken or enrich the color. Without heat treated gemstones, fine gems' availability in the most desirable colors would be scarce.
Are heat treated sapphires less valuable?
Heating is an accepted treatment for sapphire. But for fine-quality sapphire, confirmation from an independent laboratory like GIA that there is no evidence of heat adds to a sapphire's rarity and value.
Are heat treated rubies valuable?
You should assume your ruby is heated. Rubies that have a report from an independent laboratory like GIA confirming there is no evidence of heat command a premium due to their rarity. Rubies that have been diffused or are glass filled are worth less than heated rubies.
What is the difference between heated and unheated gems?
The difference between Unheated and Heated Sapphire is like the difference between processed and natural food. Natural food is always healthier than processed food. The heat-treated Sapphire lost its effectiveness almost to zero.
How do you tell if a stone has been dyed?
Another thing you can look is the colors of the gemstone. If you observed that there are areas of the gemstone where the color is extremely concentrated than the other areas of the stone, then it's likely dyed.
When did they start heat treating gemstones?
It's practically impossible to establish a precise dating of the first gemstones heating experiments. Red agates and carnelians revealing evidence of heat treatment were produced in India in 2000 B.C.; many examples were also recovered from Egyptian tombs, including treasures found with Tutankhamen (Circa 1300 B.C.).
What is the most common form of treatment for gemstones?
This article will take a look at two of the most common forms of treatment, Coating and chemical treatments. Coating . Painting and coating is an age old method of enhancing a gemstone, used as far back as Greek and Roman times, when they were considered an accepted method of further beautifying a natural gem.
What gemstones have been coated to improve their color?
Many gemstones have been routinely coated to improve or radically change their color for many years now. Topaz is a case in point. “Mystic” topaz, for example has a thin layer of titanium applied to the pavilion which causes interference effects and results in a display of rainbow colors.
What is the treatment for tanzanites?
The treatment involves applying a coating consisting of cobalt, to pale Tanzanites in order to give them the appearance of fine stones. The treatment is identifiable using an immersion cell and microscope which reveals areas where the coating hasn't taken completely or erosion has occurred near facet junctions.
What are the different types of chemical treatments?
There are five basic types of chemical treatment, namely, bleaching, dyeing, diffusion, oiling and impregnation . Bleaching is the most straightforward and is basically the use of a chemical agent to lighten or remove color or possibly dark inclusions.
How hot does a gem get?
It involves heating the gemstone up to almost melting point. So in gems like Ruby and Sapphire (Corundum) this is upwards of 1500 degrees centigrade. Once the material hits these high temperatures, the molecular structure of the material “loosens” allowing the chemical to enter the stone.
What is the best treatment for emeralds?
Oiling is by far the simplest treatment. It involves filling fractures, feathers and cracks reaching the surface layer of the stone with a liquid. In the case of Emerald, this is routinely cedar oil but can include palm oil and even olive oil.
What are some gems that are dyed?
Commonly dyed gems include lapis lazuli, opal, pearl, quartz and serpentine. Some of these gem types are naturally porous anyway and therefore don’t need to be quench crackled. Diffusion Treatments are more sophisticated and use a combination of chemicals and high temperature to enhance color.
What is a coating on a gemstone?
Coatings are added layers to gemstones that can vary widely in form and function. One of the oldest and most common gemstone coatings is wax. A layer of wax can improve luster and protect porous gems from oils in the wearer’s skin. This type of enhancement is common in cabbed gems — like turquoise, lapis lazuli, and jade — and is also routine for pearls.
Can you see colorless gems?
However, you can sometimes see an uneven layer of lacquer or polymer under a loupe or microscope. In older gems, the coating may have chips or scratches.
What is a gemstone treatment?
Treatment refers to any process other than cutting and polishing that improves the appearance of the color or clarity, or that are used to alter the appearance (color, clarity or phenomena), durability, value, or supply of a gemstone. Today, most gems are treated to improve appearance. Treatment processes can consist of heat, ...
What are the treatments for gems?
Today, most gems are treated to improve appearance. Treatment processes can consist of heat, irradiation, dyeing, oiling, or other processes. Detection of these treatments may be easy to nearly impossible. Treatments should always be disclosed to the consumer. The following are the most common treatments that are observed in the gem trade.
What is the purpose of oiling a gemstone?
The purpose is to diminish the visibly of fractures and thus improve transparency in the stone. The treatment is usually not permanent.
What is clarity enhancement?
Clarity enhancement/Fracture filling refers to the filling of surface breaking fractures or fissures with colorless glass, resin or similar substance. This process is done to improve durability, color and transparency.
What is dyeing gemstones?
Dyeing refers to one of the oldest treatments recorded. The treatment involves the introduction of a coloring agent into a gemstone to give it a new color, intensify an existing color or improve color uniformity.
What is the process of irradiating a gemstone?
Irradiation refers to the use of neutrons, gamma, and/or electron bombardment to alter a gemstone’s color. The irradiation stage of the process is then usually followed by a heating phase to effect the change. Blue topaz is typically produced by irradiation.
What is the most common method of treating gems?
Heating. The heat treatment of gems is the most common treatment technique used on gems. Reference to heat treatment of gems is found in gemological literature dating back thousands of years. However, widespread use started in the 20 th century. This treatment is usually detectable in many gems.
How long have humans treated gemstones?
Common Gemstone Treatments Cheat Sheet. Humans have treated gemstones for thousands of years. Much of the gem material currently on the market has been treated in some way before it reaches the consumer.
What are the treatments for amber?
Common treatments for amber include heat treatment, dye, and reconstitution. Coatings and fracture fillings are less common. Heat treatments darken the color and leave “sun spots.”. These spots appear like glitter within the stone. The fracture spots in this piece of amber are evidence of heat treatment.
What is the best treatment for pearls?
Pearl. The most common gemstone treatments for pearls are bleaching and dyeing. Most pearls also undergo maeshori heat treatment to enhance their luster and a gentle polishing to coat them with wax. Some pearls may also undergo non-routine treatments.
What is lapis lazuli dye used for?
Lapis Lazuli. Dyes are commonly used to hide white calcite inclusions in lapis lazuli. In addition to dye treatment, most specimens contain a coating of wax or plastic to seal in the dye. In some cases, plastic or wax may even be present in undyed specimens.
What is the best way to see cobalt in sapphire?
Cobalt or beryllium diffusion treatments can enhance sapphire color. Evidence of cobalt diffusion in blue sapphire can be seen with a Chelsea filter and by immersing the stone in RI fluid . Beryllium diffusion can create numerous colors, and the easiest way to detect this treatment is by immersion.
What color is rose quartz?
Any variety of quartz can undergo irradiation to form smoky quartz. Irradiation and heat can produce numerous colors, including yellow-green “lemon” quartz and yellow to red varieties. Heat treatment of amethyst can produce prasiolite (green quartz) as well as citrine. There are no known treatments of rose quartz.
How to improve tiger eye color?
Tiger’s eye may receive treatment to improve its color. Heat treatment can help develop red colors. Bleach can lighten darker stones. In addition, dyes can enhance or alter the gem’s color.
What is the color of a gemstone?
The most extensively studied gemstone diffusion treatment involves the migration of the element beryllium into sapphire. The result creates a new color in the material, frequently orange but also blue, yellow, or red. In large stones, you can see the altered color zone as a surface layer through immersion in a refraction liquid. However, in small stones, the beryllium may penetrate through the entire body, so they have no visible color zones.
What is green amethyst?
Although amethyst may turn brownish or red at a temperature between 400 and 500° C, sometimes it turns a green color. While such heated gems are sometimes called “greened amethyst” or “green amethyst,” these are misnomers. Green quartz is properly known as prasiolite.
What color does tourmaline turn?
Heating usually lightens the color of tourmaline but can also sometimes turn a dark green stone an attractive, emerald-like color. Gamma irradiation of tourmaline produces spectacular color changes. Pale pink and some colorless stones may turn dark pink.
What is green quartz?
Green quartz is properly known as prasiolite. Further heating of these gems causes a complete loss of color. Irradiation plus heating may also produce brown, orange, and yellow hues in quartz. The heating of amethyst to a brownish yellow color occurs on a commercial scale.
How does smoky quartz turn into amethyst?
Specially prepared smoky quartz can turn into amethyst via gamma-ray bombardment. In fact, it appears likely that natural amethyst acquires its color in the same manner. Gamma irradiation plus heating of some Brazilian quartz produces a bright, greenish yellow color not found in nature.
What color is Tanzanite?
Heating certain crystals, which eliminates the red-violet color component, produces the lively sapphire-blue color that has made the gem so popular.
Can turquoise be colored?
Turquoise can receive color enhancements in many ways. Techniques such as soaking in wax (paraffin) or impregnating with plastics are often referred to as “stabilization.”. Although you can usually detect such methods, suspect them whenever a deep-color turquoise comes with a modest price.
What is the name of the coating on a gemstone?
The most commonly known versions are the “Aqua Aura”, “Mystic” or “Azotic” coatings which give the gem an iridescent look. These more “metallic” coatings give a look which no natural gem has and are easily identified by those with some experience with gemstones.
What is enhancement in gemstones?
What does “enhancement” mean in the gem trade? ENHANCEMENT: Any treatment process other than cutting and polishing that improves the appearance (color/clarity/phenomena), durability, or availability of a gemstone. ...
What gemstones are irradiated?
Irradiating gems after they were mined either replicates this process or takes it to another level. The gemstone “poster child” for irradiation is blue topaz. Irradiated blue topaz is so prevalent in the market that it is presumed that any topaz with a medium to deep blue color has received this treatment.
How do you feel about a gem that has been enhanced?
Philosophically the question is, how do you feel about a gem that has been “enhanced”? This “philosophical feel” is the largest problem that most people have with gemstone enhancements . While many individuals will accept common and durable treatments as valid and reasonable, there are still those who for holistic, religious or emotional reasons want a gem that has not undergone any “improvements” other than cutting.
Why do you heat a gemstone?
Heating is also used in specific gemstone types (for example Spinel and Sapphire) to improve the clarity and brilliance of the finished gem by dissolving microscopic graining or particles (especially rutile) inside the crystal.
What is the oldest form of gemstone enhancement?
Heating is probably the oldest form of gemstone enhancement. It is impossible to tell who first allowed a gem to fall into a fire and then, in amazement, observed the resulting change of color. What is clear though is that the heating of gemstones has been going on for many centuries and, depending on the gem type, is often accepted as “routine” by those in the gem trade.
What is the difference between enhanced and un enhanced sapphires?
Financially the difference between an enhanced and un enhanced gem can be either quite large or small to non existent. Sapphires for example will usually command a 30%-80% premium if they have not been heat treated when comparing a heated one of the same color to its purely “natural” un enhanced counterpart. Why then do people ever heat sapphires? Heat will often result in a sapphire that is a different shade of color and/or clearer and consequently brighter and so certain sapphires with specific characteristics can have their beauty and salability increased by heating. If sapphire enhancement by heating does not bother you then you can get a beautiful heated gem for significantly less money than an equally beautiful one that hasn’t been heated. In other cases, such as brighter yellow or orange Citrine, heat treatment is almost universal and so the market doesn’t have a special price bracket for unheated material.
What is gemstone treatment?
It has been cut or polished to bring out its sparkle and color. When we talk about gemstone treatments, though, we refer to treatments which enhance color or clarity.
What is heat treated gemstone?
Heat treating is usually done to change or enhance color in a gemstone. Some gemstones are also “created” through this process. Citrine for example is generally heat-treated smoky quartz or amethyst. It has an entirely different color or appearance prior to being heat treated.
What is the process of bleaching a gemstone?
Bleaching is a process that removes color from a gemstone. It is usually done in combination with dyeing. Gemstones which are commonly bleached include jadeite jade (to remove unwanted brown coloration), pearls, coral, chalcedony, and tiger’s eye. Some of these are only bleached to lighten their color.
What gemstones are dyed?
Many types of gemstones are dyed, including pearls, quartz, lapis lazuli, turquoise, and more. Quite often when you see a bright, unexpected color in a gemstone, you should suspect dyeing. If you have ever been to a rock shop and looked at the tumbled gemstones, odds are you have encountered a lot of cheaply dyed gems.
What does it mean when a gemstone is cut?
Any gemstone you purchase that isn’t in its raw state has in a sense been enhanced by a jeweler. It has been cut or polished to bring out its sparkle and color.
What stones are impregnated?
This can also make the gemstone more durable. You will commonly encounter impregnation on stones like turquoise, lapis lazuli, nephrite, serpentine, and amazonite. If you have handled a few of these gemstones, you know from experience that there is a certain “graininess” to their texture. This is the porous attribute.
What is the treatment for porous gemstones?
This is a treatment done to some porous gemstones. It involves the use of wax, plastic or polymer. The wax or other substance being used is poured over the stone to fill the porous spots and create a smoother texture and appearance. This can also make the gemstone more durable.
Coating
Dyeing
- Dyeing refers to one of the oldest treatments recorded. The treatment involves the introduction of a coloring agent into a gemstone to give it a new color, intensify an existing color or improve color uniformity.
Clarity Enhancement/Fracture Filling
- Clarity enhancement/Fracture filling refers to the filling of surface breaking fractures or fissures with colorless glass, resin or similar substance. This process is done to improve durability, color and transparency.
Heating
- The heat treatment of gems is the most common treatment technique used on gems. Reference to heat treatment of gems is found in gemological literature dating back thousands of years. However, widespread use started in the 20thcentury. This treatment is usually detectable in many gems. Heat treated gems are stable and the treatment is usually permanent. The vast majority o…
Flux Healing
- This treatment typically occurs in ruby and sapphire during the heat treatment with flux components melting into and solidifying on the surface reaching fractures of the stone. In many cases this would improve the clarity by “healing” the fractures.
Diffusion Treatment
- This treatment is achieved by heating sapphire extremely high temperatures while adding certain elements such as beryllium, chromium and/or titanium to the process. Currently detection of Be-diffusion is only possible using LA-ICP-MS and LIBS which are highly advanced and expensive spectroscopy techniques. On the contrary, Ti-diffusion treatment is generally detectable using m…
Irradiation
- Irradiation refers to the use of neutrons, gamma, and/or electron bombardment to alter a gemstone’s color. The irradiation stage of the process is then usually followed by a heating phase to effect the change. Blue topaz is typically produced by irradiation.
Oiling
- Oiling refers to a filling of surface reaching cracks or fissures in a gem with a colorless oil or resin, wax or other substance except glass or plastic, to improve the gemstone’s appearance. The purpose is to diminish the visibly of fractures and thus improve transparency in the stone. The treatment is usually not permanent.