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Gems TV

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ENHANCEMENTS, TREATMENTS & CARE

Skilfully merging art and science, a variety of techniques are used to help gemstones reach their full potential. As critical as good cutting, enhancements and treatments are an integral part of the modern gemstone industry.

With its roots in antiquity (e.g. heat treatment has been practiced in India for over 4,000 years), most of the techniques used simply facilitate the beautiful end results of the earth's natural processes. Below are some answers to common gemstone enhancement, treatment and care questions.


Is the use of enhancements and treatments globally accepted?

As long as they are disclosed, all permanent enhancements and treatments are globally accepted. As the majority of gemstones traded internationally have undergone some form of enhancement, always assume treatments when purchasing gemstones.


Are all enhancements and treatments permanent?

With the exception of Emeralds, whose beauty is enhanced and easily maintained by the application of oils or polymers, GemsTV only knowingly accepts enhancements and treatments that are permanent with normal wear. Our information sources for gem enhancements and treatments include university mineralogical, gemmological and geology departments, gem laboratories, trade associations, regulatory bodies, professional journals, books, the internet, and individual experts.


Do enhancements or treatments affect a gem's value?

For some varieties there is no difference between the values of enhanced, treated or natural gemstones. However, high quality unheated Rubies and Sapphires are extremely rare and command a much higher market price. When purchasing Rubies and Sapphires, please be aware that unheated/untreated specimens are almost non-existent, and as a result, always purchase from a reliable source or have the seller's claim verified by a gemmologist.


How do I care for my gemstone jewellery?

Caring for your gemstone jewellery (i.e. normal wear) is a matter of common sense and simple precaution. For gemstone specific care instructions, please refer to the table below.

  • Always remove your jewellery when engaging in activities that risk impact or exposure to chemicals or heat such as sports or housework.
  • Always put jewellery on after using cosmetics, hair spray or perfumes, not before.
  • Never remove your jewellery by pulling on the gems.
  • Never store your jewellery in heaps and always store your gem necklaces flat. The best way to store your gemstone jewellery is in the separate compartments of a jewellery box or in cloth pouches.
  • Carefully wipe jewellery with a soft lint-free cloth after each wearing to remove oils and salts.
  • Once in a while, take the time to clean your jewellery. Always clean your jewellery with a cleaning solution or mechanical cleaner suitable for the gem.


What are mechanical cleaners?

The most common mechanical cleaners are ultrasonic and steam cleaners. Ultrasonic cleaners feature two basic parts: a small motor and a cleaning tank. The machine's motor produces ultrasonic energy that is transmitted with vibrating energy waves (usually 40,000 sound waves per second) to create microscopic bubbles in the cleaning tank. Called cavitation, this motion knocks dirt off the jewellery and is very effective in penetrating the tiny crevices in jewellery that traditional cleaning cloths and topical cleaners cannot easily reach. A steam cleaner uses jets of steam to literally blast dirt off jewellery. As some gemstones can be damaged by mechanical cleaners, always check to see if your gemstone is suitable.


How are gemstones enhanced or treated?

The following table shows the enhancements and treatments used for some popular gemstones, their purpose, frequency and care.


GEMSTONE HARDNESS TREATMENT EXPLANATION CARE STEAM CLEANING ULTRASONIC CLEANING
AGATE (DENDRITIC, FIRE, IRIS & MOSS) 6.5 - 7 Not treated. N/A Normal care. Yes. No.
ALEXANDRITE 8.5 Colourless oil, wax and resin in fissures. Used to improve appearance, these treatments are rarely used. Normal care. Yes. No.
AMAZONITE 6 - 6.5 Colourless wax or oil, paraffin or hardened resin and/or impregnated with colourless plastic or hardened resin. Used to improve appearance, colourless wax or oil is usually applied while impregnation with colourless plastic or hardened resin is occasionally applied. Normal care. Yes. No.
AMBER 2 - 2.5 Dyed, surface treated or heated. Used to improve appearance and/or to deepen colour, dying and surface treatments are rarely applied while heating is usually applied. Normal care. Coated gemstones are not suitable for re-cutting or re-polishing. No. No.
AMBYGLONITE 5.5 - 6 Not treated. N/A Normal care. Some gemstones are prone to damage due to thermal shock. Do not expose them to extreme temperature changes. Yes. No.
AMETHYST 7 Heated. Used to lighten colour and/or to remove smokiness, this treatment is only occasionally applied. Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. No.
AMETHYST (GREEN) 7 Heated or irradiated. This treatment provides/improves colour and appearance and is usually applied. Normal care. Yes. No.
AMETRINE 7 Heated. Rarely used to improve colour. Normal care. Yes. No.
AMMOLITE 4 Impregnated with colourless hardened substances. This treatment is commonly used to increase stability. Normal care. Coated gemstones are not suitable for re-cutting or re-polishing. Yes. No.
ANATASE 5.5 - 6 Not treated. N/A N/A N/A N/A
ANDALUSITE 7 - 7.5 Not treated. N/A Normal care. Yes. No.
ANDESINE 6 - 6.5 Heated or bulk diffusion of Fe/Cu Sometimes used to provide/improve colour. Normal care. Yes. No.
ANGLESITE 2 - 3 Not treated. N/A Very fragile, handle with care. N/A N/A
APATITE 5 Heated. Usually applied, this treatment improves appearance and/or deepens colour. Normal care. No. No.
APOPHYLLITE 4.5 - 5 Not treated. N/A Very fragile, handle with care. No. No.
AQUAMARINE 7.5 - 8 Heated. Used to remove yellow components to produce a purer blue colour, this treatment is usually applied. Normal care. Yes. No.
ARAGONITE 3.5 - 4 Not treated. N/A Normal care. Yes. No.
AVENTURINE 7 Not treated. N/A Normal care. Yes. Yes.
AVENTURINE (BLACK) 7 Irradiated. Usually applied, this treatment is used to change colour. Normal care. Yes. Yes.
AXINITE 6 - 7 Not treated. N/A Normal care. Yes. No.
AZURITE 3.5 - 4 Surface colourless waxing and/ or impregnated with colourless oil, wax or resin. Used to improve appearance, surface colourless waxing is commonly applied while impregnation with colourless oil, wax or resin is rarely applied. Normal care. Yes. No.
AZURMALACHITE (AZURITE MALACHITE) 3.5 - 4 Surface waxing and/or impregnated with colourless plastic or hardened resin. Used to improve stability, durability, lustre and/or colour, surface waxing is commonly applied while impregnation with colourless plastic or hardened resin is rarely applied. Normal care. Yes. No.
AZURITE (DRUZY) 3.5 - 4 Not treated. N/A N/A N/A N/A
BARITE 2.5 - 3.5 Not treated. N/A Very fragile, handle with care. N/A N/A
BASTNAESITE 4 - 4.5 Not treated. N/A Very fragile, handle with care. N/A N/A
BIXBITE 7.5-8 Colourless oil and resin. This treatment is commonly used to improve appearance. Normal care. No. No.
BLOODSTONE 6.5 - 7 Not treated. N/A Normal care. Yes. No.
BORACITE 7 - 7.5 Not treated. N/A N/A N/A N/A
BRAZILIANITE 5.5 Not treated. N/A Very fragile, handle with care. N/A N/A
BURBANKITE 3.5 - 4 Not treated. N/A Very fragile, handle with care. N/A N/A
BUSTAMITE 3.32 - 3.43 Not treated. N/A Very fragile, handle with care. N/A N/A
CALCITE 3 Not treated. N/A Very fragile, handle with care. Yes. No.
CASSITERITE 6 - 7 Not treated. N/A Normal care. Yes. No.
CELESTITE 3 - 3.5 Not treated. N/A Very fragile, handle with care. N/A N/A
CHALCEDONY (BLUE & GREEN) 6.5 - 7 Dyed. This treatment is commonly used to improve colour. Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. Yes.
CHAROITE 6 Not treated. N/A Normal care. Yes. No.
CHRYSOBERYL (BROWN, GREEN, YELLOW) 8.5 Not treated. N/A Normal care. Yes. No.
CHRYSOBERYL (CAT’S EYE) 8.5 Irradiated. Uncommonly applied, this treatment is used to change colour and to improve chatoyancy. Normal care. Yes. No.
CHRYSOCOLLA 2 - 4 Surface colourless waxing and/or impregnation with colourless plastic or hardened resin. Used to improve appearance, these treatments are occasionally applied. Normal care. Yes. No.
CHRYSOPRASE 6.5 - 7 Not treated. N/A Normal care. Yes. Yes.
CINNABAR 2 - 2.5 Not treated. N/A Very fragile, handle with care. N/A N/A
CITRINE 7 Heated or irradiated. Usually applied, this treatment produces colour. Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. No.
CLINOHUMITE 6 Not treated. N/A N/A N/A N/A
CORNELIAN 6.5 - 7 Heated and/or dyed. Used to produce colour, heating is usually applied while dying is occasionally applied. Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. No.
CREEDITE 4 N/A N/A N/A N/A N/A
DANBURITE (WHITE) 7 - 7.5 Not treated. N/A Normal care. Yes. No.
DANBURITE (BROWN) 7 - 7.5 Irradiated. Commonly applied to improve appearance. Normal care. Yes. No.
DATOLITE 5 - 5.5 Not treated. N/A Normal care. Yes. No.
DIAMOND (COLOR ENHANCED) 10 The process known as colour enhancement involves using clean Diamonds and modifying their colour with a combination of electron bombardment and heat, using safe electron-accelerator technology. This process exactly duplicates the natural exposure of Diamond crystals to radioactive elements during their formation. Used to improve colour intensity or to produce unique colours, this treatment is always applied. Normal care. Yes. Yes.
DIAMOND 10 Laser drilled. This is occasionally used to improve appearance. Normal care. Yes. Yes.
DIAMOND (WHITE TO FAINT YELLOW) 10 Coated, pressure heated and fractured filled. Used to disguise off-colour, coatings are rarely applied. Fracture filling is occasionally applied to improve clarity and pressure heating is rarely applied to improve clarity. Normal care. Coated gemstones are not suitable for re-cutting or re-polishing. Yes. No.
DIASPORE (ZULTANITE) 6.5 - 7 Not treated. N/A Normal care. Yes. No.
DIOPSIDE 5 - 6 Not treated. N/A Normal care. Yes. No.
DOLOMITE 3.5 - 4 Not treated. N/A N/A N/A N/A
DUMORTIERITE 7 - 8.5 Not treated. N/A Normal care. Yes. No.
EKANITE 6 - 6.5 N/A N/A N/A N/A N/A
EMERALD 7.5 - 8 Colourless oil, polymer, wax and/or resin in fissures, and/or dyed with the use of coloured oil, and/or open fractures or cavities filled with hardened resin. These treatments improve appearance. Colourless oil, polymer, wax and/or resin in fissures are usually applied. Dying with the use of coloured oil is occasionally applied. Open fractures or cavities filled with hardened resin is commonly applied. Normal care. No. No.
ENSTATITE 5 - 6 Not treated. N/A Normal care. Yes. No.
EOSPHORITE 5 Not treated. N/A N/A N/A N/A
EPIDOTE 6 - 7 Not treated. N/A Normal care. Yes. No.
EUCLASE 7.5 Not treated. N/A Normal care. Yes. No.
EUDIALYTE 5.5 Not treated. N/A N/A N/A N/A
FIRE BERYL? 7.5 - 8 Not treated. N/A Normal care. Yes. No.
FLUORITE (BLUE, GREEN & PURPLE) 4 Irradiated or heated. Commonly applied, this treatment provides colour. Normal care. Yes. No.
FLUORITE (WHITE) 4 Not treated. N/A Normal care. Yes. Yes.
FOSSILS N/A Not treated. N/A N/A N/A N/A
GAHNITE 7.5 - 8 Not treated. N/A Normal care. Yes. No.
GARNET 7 - 7.5 Not treated. N/A Normal care. Some gemstones are prone to damage due to thermal shock. Do not expose them to extreme temperature changes. No. No.
GENTHELVITE 6 - 6.5 N/A N/A N/A N/A N/A
GLACIER TOPAZ? 8 Not treated. N/A Normal care. No. No.
HAUYNE 5 - 6 Not treated. N/A N/A N/A N/A
HELIODOR (CAT’S EYE) 7 - 7.5 Not treated. N/A Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. Yes.
HELIODOR 7 - 7.5 Irradiated. Usually applied, this treatment provides colour. Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. Yes.
HEMATITE 5.5 - 6.5 Not treated. N/A Normal care. Yes. No.
HEMIMORPHITE 5 Not treated. N/A N/A N/A N/A
HERDERITE 5 - 5.5 Not treated. N/A N/A N/A N/A
HIDDENITE 6.5 - 7 Irradiated. Rarely used, this treatment improves and/or provides colour and uniformity. Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. No.
HOWLITE (BLUE) 3 - 3.5 Dyed. Commonly applied, this treatment is used to imitate Turquoise or Lapis Lazuli. Normal care. No. No.
HOWLITE (WHITE) 3 - 3.5 Not treated. N/A N/A N/A N/A
IDOCRASE 6.5 Not treated. N/A Normal care. Yes. No.
IOLITE 7 - 7.5 Not treated. N/A Normal care. Yes. Yes.
JADEITE (JADE) 6.5 - 7 Colourless polymer impregnation and/or polymer and colourless polymer impregnation followed by acid treatment and/or dyed. Commonly applied, this treatment improves colour and uniformity. Normal care. Yes. No.
JASPER 6.5 - 7 Dyed. Commonly applied, this treatment is used to imitate other gemstones. Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. No.
JASPER (MULTI-COLORED) 6.5 - 7 Not treated. N/A Normal care. Yes. No.
KORNERUPINE 6.5 - 7 Not treated. N/A Normal care. Yes. No.
KUNZITE 6.5 - 7 Heated or irradiated. Commonly applied, this treatment improves and/or darkens colour. Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. No.
KUNZITE (GREEN & CAT’S EYE) 6.5 - 7 Not treated. N/A Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. No.
KYANITE 4 - 7 Not treated. N/A Normal care. Yes. No.
LABRADORITE 6 - 6.5 Surface colourless waxing. Occasionally applied to improve appearance. Normal care. Yes. No.
LAPIS LAZULI 5 - 6 Surface colourless waxing and/or dyed. Commonly applied, this treatment is used to provide colour and/or colour uniformity. Normal care. Yes. No.
LARIMAR 5 Not treated. N/A N/A N/A N/A
LEIFITE 6 N/A N/A N/A N/A N/A
MAGNESITE 3.5 - 4 Not treated. N/A N/A Yes. Yes.
MALACHITE 3.5 - 4 Surface colourless waxing and/or impregnated with colourless plastic or hardened resin. These treatments are used to improve the gem’s colour. Surface colourless waxing and/or coating with colourless wax are occasionally applied. Impregnation with colourless plastic or hardened resin is rarely applied. Normal care. Yes. No.
MAMMOTH IVORY 2 - 3 Impregnated with colourless plastic or hardened resins and/or colourless surface waxing and/or dyed and/or bleached. These treatments are commonly used to increase stability. Impregnation with colourless plastic or hardened resin and bleaching are commonly applied. Colourless surface waxing and dying are occasionally applied. Normal care. No. No.
MANGANOTANTALITE 6 - 6.5 Not treated. N/A N/A N/A N/A
MARCASITE 6 - 6.5 Not treated. N/A Normal care. Yes. Yes.
MAWSITSIT 6 - 8 Not treated. N/A Normal care. Yes. No.
MELLITE 2 - 2.5 N/A N/A Very fragile, handle with care. N/A N/A
MILARTE 5.5 - 6 N/A N/A N/A N/A N/A
MOLDAVITE 5.5 - 6.5 Not treated. N/A Normal care. Yes. Yes.
MONAZITE 5 - 5.5 Not treated. N/A N/A N/A N/A
MONTEBRASITE 5.5 - 6 Not treated. N/A Normal care. Some gemstones are prone to damage due to thermal shock. Do not expose them to extreme temperature changes. No. No.
MOOKITE 6.5 N/A N/A N/A N/A N/A
MOONSTONE 6 - 6.5 Not treated. N/A Normal care. Yes. No.
MORGANITE 7.5 - 8 Heated or irradiated. Commonly applied, this treatment eliminates yellow overtones. Normal care. Yes. No.
MORGANITE (GREEN) 7.5 - 8 Cobalt heated. Always applied, this treatment induces a vivid green colour. Normal care. Yes. No.
NATROLITE 5 - 5.5 Not treated. N/A N/A Yes. Yes.
NEPHRITE (JADE) 6.5 - 7 Dyed and/or impregnated with colourless oil, wax or resin. Rarely used, this treatment improves colour and uniformity. Normal care. Yes. No.
NEPHRITE (CAT’S EYE JADE) 6.5 - 7 Not treated. N/A Normal care. Yes. No.
NUUMMIT 5 - 6 Not treated. N/A Normal care. Yes. No.
OBSIDIAN 5.5 - 7 Not treated. N/A Normal care. Yes. No.
OLIGOCLASE 6 - 6.5 Not treated. N/A Normal care. Yes. No.
ONYX 6.5 - 7 Dyed. Always applied, this treatment is used to achieve colour uniformity. Normal care. Yes. Yes.
OPAL (BLACK, SEMI-BLACK & WHITE) 5.5 - 6 Impregnated with colourless oil, wax, plastic or resin. Used to improve durability, appearance and colour, this treatment is rarely applied. Normal care. Some gemstones are prone to crack due to loss of structural water. Keep away from heat and drying environments. Some gemstones are prone to damage due to thermal shock. Do not expose them to extreme temperature changes. No. No.
OPAL (BOULDER) 5.5 - 6 Infusion of unhardened colourless substances into voids. Used to improve appearance, this treatment is occasionally applied. Normal care. Some gemstones are prone to crack due to loss of structural water. Keep away from heat and drying environments. Some gemstones are prone to damage due to thermal shock. Do not expose them to extreme temperature changes. No. No.
OPAL (CAT’S EYE) 5.5 - 6 Impregnated with colourless plastic. Used to improve durability and colour, this treatment is usually applied. Normal care. Some gemstones are prone to crack due to loss of structural water. Keep away from heat and drying environments. Some gemstones are prone to damage due to thermal shock. Do not expose them to extreme temperature changes. No. No.
OPAL (FIRE & MOSS) 5.5 - 6 Not treated. N/A Normal care. Some gemstones are prone to crack due to loss of structural water. Keep away from heat and drying environments. Some gemstones are prone to damage due to thermal shock. Do not expose them to extreme temperature changes. No. No.
PARISITE 4.5 N/A N/A N/A N/A N/A
PEARL (CULTURED) 2.5 - 4.5 Bleached, dyed, chemically treated or irradiated. Occasionally used, these treatments improve and/or change colour and/or colour uniformity. Clean either by wiping gently with a moist cloth or rinsing and gently patting dry with a soft cloth. No. No.
MOTHER OF PEARL 2.5 - 4.5 Coated, dyed or bleached. Occasionally used, these treatments improve and/or change colour and/or colour uniformity. Clean either by wiping gently with a moist cloth or rinsing and gently patting dry with a soft cloth. No. No.
PECTOLITE 4.5 - 5 Not treated. N/A N/A N/A N/A
PERIDOT 6.5 - 7 Heat, colourless oil, wax or resin in fissures, and/or filled fractures with colourless hardened resin. Used to improve appearance, these treatments are rarely applied. This includes heating to oxidise specific minerals to enhance colour. Normal care. Some gemstones are prone to damage due to thermal shock. Do not expose them to extreme temperature changes. No. No.
PETALITE 6 - 6.5 N/A N/A N/A N/A N/A
PEZZOTTAITE 8 Not treated. N/A Normal care. No. No.
PHENAKITE 7.5 - 8 Not treated. N/A. Normal care. Yes. Yes.
POLLUCITE 6.5 - 7 Not treated. N/A N/A N/A N/A
PRASIOLITE 7 Heated. This treatment improves colour and appearance and is usually applied. Normal care. Yes. No.
PREHNITE 6 - 6.5 Not treated. N/A Normal care. Yes. No.
PYRITE 6 - 6.5 Not treated. N/A Normal care. Yes. No.
PYROXMANGITE 5.5 - 6 Not treated. N/A N/A N/A N/A
QUARTZ 7 Heated, irradiated or coated. Occasionally applied, this treatment improves colour or produces unique colours. Normal care. Gemstones with superficial colour (or phenomena) surface layers are not suitable for re-cutting or re-polishing. Yes. No.
QUARTZ (BLUE MOON) 7 Heated. This treatment provides/improves colour and appearance and is usually applied. Normal care. Yes. No.
QUARTZ (CAT’S EYE, RUTILATED & ROSE) 7 Not treated. N/A Normal care. Yes. No.
QUARTZ (SMOKY) 7 Irradiated. Used to alter colour, this treatment is occasionally applied. Normal care. Yes. No.
QUARTZITE 7 Dyed and/or impregnated with colourless plastic or hardened resin. Used to improve appearance, this treatment is occasionally applied. Normal care. Yes. No.
REMONDITE 3 - 3.5 Not treated. N/A N/A N/A N/A
RHODOCHROSITE 7 Not treated. N/A Normal care. Yes. No.
RHODONITE 7 Dyed. Used for colour uniformity, this treatment is occasionally applied. Normal care. Yes. No.
RUBY 9 Heated and/or the healing of fissures and/or glass filled open fractures and cavities, and/or dyed and/or bulk diffusion of certain additives during the heating process, and/or colourless oil or resin in fissures. Usually applied, these treatments produce, intensify or lighten colour and/or improve colour uniformity and/or appearance. Examples of the additives used include beryllium to permanently improve colour and borax to improve appearance. Normal care. Fillers in voids/cavities, fissures and/or open fractures can scratch more easily than the host gem or be more vulnerable to damage from heat or some chemicals. Yes. Yes.
RUBY (MADAGASCAN, MAJESTIC, MOZAMBIQUE & ROYAL) 9 Classified as composite gemstones, these Rubies are treated using heat and a high refractive index lead-glass to fill fractures and cavities and/or the bulk diffusion of certain additives (e.g. beryllium) during the heating process. Always applied, this treatment vastly improves the apparent clarity and potentially adds weight and/or intensifies colour and/or colour uniformity and/or appearance. The lead-glass is typically yellow to orange in colour and can artificially augment the red colour of these gems. Normal care. Fillers in voids/cavities, fissures and/or open fractures can scratch more easily than the host gem or be more vulnerable to damage from heat or some chemicals. The lead-glass may be damaged by a variety of solvents. No. No.
SAPPHIRE 9 Heated and/or the healing of fissures and/or glass filled open fractures and cavities, and/or dyed and/or bulk diffusion of certain additives during the heating process, and/or colourless oil or resin in fissures. Usually applied, these treatments produce, intensify or lighten colour and/or improves colour uniformity and/or appearance. Examples of the additives used include beryllium to permanently improve colour and borax to improve appearance. Normal care. Fillers in voids/cavities, fissures and/or open fractures can scratch more easily than the host gem or be more vulnerable to damage from heat or some chemicals. Yes. Yes.
SARD 6.5 - 7 Dyed or heated. This treatment is used to provide colour. Heating is usually applied while dying is occasionally applied. Normal care. Yes. No.
SARDONYX 6.5 Dyed. Usually applied, this treatment improves colour. Normal care. Yes. No.
SCAPOLITE (YELLOW) 5.5 - 6 Not treated. N/A Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. No.
SCAPOLITE (VIOLET) 5.5 - 6 N/A N/A N/A N/A N/A
SCHEELITE 4.5 - 5 Not treated. N/A N/A N/A N/A
SCOLECITE 5 - 5.5 Not treated. N/A N/A N/A N/A
SELLAITE 5 - 6 Not treated. N/A N/A N/A N/A
SENARMONTITE 2 - 2.5 Not treated. N/A Very fragile, handle with care. N/A N/A
SERANDITE 4.5 N/A N/A N/A N/A N/A
SHELL (PINK) 4 Dyed. Often applied to improve colour. Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. No.
SHORTITE 3 Not treated. N/A N/A N/A N/A
SIDERITE 4 Not treated. N/A N/A N/A N/A
SILLIMANITE 6 - 7 Not treated. N/A Normal care. Yes. No.
SINHALITE 6.5 - 7 Not treated. N/A Normal care. Yes. No.
SMITHSONITE 4 - 5 Not treated. N/A Normal care. Yes. No.
SODALITE 5.5 - 6 Dyed. Rarely applied, this treatment is used to improve colour. Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. No.
SPECTROLITE 6 - 6.5 Surface colourless waxing. Occasionally applied to improve appearance. Normal care. No. No.
SPHALERITE 3.5 - 4 Not treated. N/A Very fragile, handle with care. Yes. No.
SPHENE 5 - 5.5 Not treated. N/A Normal care. Yes. No.
SPINEL 8 Not treated. N/A Normal care. Yes. No.
STAUROLITE 7 - 7.5 Not treated. N/A N/A N/A N/A
SUGILITE 6 - 6.5 Not treated. N/A Normal care. Yes. No.
SUNSTONE 6 - 6.5 Not treated. N/A Normal care. Yes. No.
TANOLITE? 7 - 7.5 Not treated. N/A Normal care. Yes. No.
TANZANITE 6.5 - 7 Heated. Usually applied, this treatment produces the colours for which this gem is known. Normal care. Some gemstones are prone to damage due to thermal shock. Do not expose them to extreme temperature changes. No. No.
THAUMASITE 3.5 N/A N/A N/A N/A N/A
TIGER’S EYE 7 Dyed, bleached or heated. Used to improve colour, these treatments are commonly applied. Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. No.
TIGER’S EYE (VIOLET) 7 Heated. This treatment is occasionally applied to improve colour. Normal care. Yes. Yes.
TITANIUM (DRUZY) 7 Titanium coated. This treatment permanently produces a rainbow effect on the surface of the gem. Normal care. No. Yes.
TOPAZ (EXCEPT WHITE) 8 Irradiated, heated, coated and/or diffused. Used to improve colour intensity or to produce unique colours, these treatments are usually applied. Physical Vapour Deposition (PVD) coating involves the application of a bonded layer of fine titanium atoms (US Patent Number 5,853,826 for Azotic Coating Technologies Inc.). When this oxide treatment falls within a certain thickness, optical interference produces a variety of colours. Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Gemstones with superficial colour (or phenomena) surface layers are not suitable for re-cutting or re-polishing. No. No.
TOURMALINE 7 - 7.5 Heated and/or irradiated and/or filling of colourless oil, resin and wax in fissures, and/or cavities/fractures filled with colourless hardened substances. Used to improve colour intensity and appearance these treatments are commonly applied. Normal care. Yes. No.
TOURMALINE (CAT’S EYE, CHROME, MULTI COLOR, PARTY & WATERMELON) 7 - 7.5 Not treated. N/A Normal care. Yes. No.
TREMOLITE 5 - 6 Not treated. N/A Normal care. Yes. No.
TUGTUPITE 4 Not treated. N/A Normal care. Yes. No.
TURQUOISE 5 - 6 Impregnated with plastic and/or surface colourless waxing and/or dyed. These treatments improve stability, durability, lustre and/or colour. Impregnation with plastic and surface colourless waxing are commonly applied. Dying is rarely used. Normal care. Yes. No.
UNAKITE 6 - 7 Not treated. N/A Normal care. Yes. Yes.
VESUVIANITE 6.5 Not treated. N/A Normal care. Yes. No.
VILLIAUMITE 2 - 2.8 Not treated. N/A N/A N/A N/A
WILLEMITE (BLUE) 5.5 Heated. This treatment is used to change the colour from white to blue. Normal care. Some gemstones are prone to damage due to thermal shock. Do not expose them to extreme temperature changes. No. No.
WILSONITE 3 - 4 Not treated. N/A N/A N/A N/A
WULFENITE 2.28 - 2.4 Not treated. N/A Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. No.
ZIRCON (BLUE, RED, WHITE & YELLOW) 6.5 - 7 Heated. Used to improve colour this treatment is always applied. Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. No.
ZIRCON (BROWN & GREEN) 6.5 - 7 Not treated. N/A Normal care. Some gemstones fade or revert to their original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions. Yes. No.
ZULTANITE 6.5 - 7 Not treated. N/A Normal care. Yes. No.
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