Gemstone Treatments, Enhancements, and Care AGTA

Gemstone Treatments, Enhancements, and Care

**Just as wood furniture needs to be lacquered, many gemstones require finishing before they are ready to be sold. As critical as good cutting and polishing is, treatments have become an integral part of the modern gemstone industry. Akin to aging fine wine, most of the techniques used simply facilitate the beautiful end results of the Earth’s natural processes.
While these treatments are taken as commonplace within the industry, the general public's awareness has been much lower. This page provides clear answers to common treatment questions.

Is The Use Of Treatments Globally Accepted?

Yes, with close to 99% of the more popular gem types being treated, all permanent techniques are universally accepted. The majority of gemstones traded internationally have undergone some form of treatment. Always assume treatment when purchasing gemstones. In fact, some techniques such as heating are centuries old. In all likelihood, even your grandmother’s Ruby ring has been heat-treated.

Are All The Treatments Used Permanent?

Except for Emeralds that are treated with colorless oil or polymers, most gemstone treatments are permanently stable with normal wear. Please see gemstone care, listed below, to learn how to properly care for your jewelry and gemstones.

Why Some Natural Gemstones Are Treated

Treatments are most commonly used to improve the color or appearance of the finished product. Some gemstones simply would not exist in salable quantities without treatment. For example, heating greenish brown Zoisite to 600 degrees Celsius produces the currently popular vibrant violet-blue Tanzanite. No heating, no Tanzanite! Please note that the term “natural gemstones” refers to those formed in the earth, whether or not they have been treated after mining. This does not apply to created or simulated gems.

How Treatments Can Affect A Gemstone’s Value

Interestingly, in some precious and semi-precious colored gemstones, there is no variation between the value of treated and untreated material. Treatments may even increase a gem’s value. For example, when Zoisite is heated, vibrant violet blue Tanzanite is the end product. These gems then command a far higher market value. However, on the other hand, high quality unheated Rubies and Sapphires are extremely rare and command a much higher market price. When purchasing high quality Rubies and Sapphires, always keep in mind that unheated material is almost non-existent. Always purchase your gems from a reliable supplier who guarantees their gemstones, or have the seller’s claim verified by a qualified expert. However, for most of us, treatments are a godsend, as they make gems more available.

The Following Gemstones Should NOT Be Treated

Alexandrite
Allanite
Amblygonite
Ametrine
Anatase
Andalusite
Apatite
Aventurine
Axinite
Azurite Malachite
Boracite
Brazilianite
Cassiterite
Chalcedony
Chrome Diopside
Chrysoberyl
Chrysocolla
Chrysoprase
Cinnabar
Clinohumite
Danburite
Diamond
Enstatite (Cats Eye)
Eosphorite
Epidote

Euclase
Fluorite
Gahnite
Garnet
Goshenite
Hematite
Herderite
Hiddenite
Howlite
Iolite
Kunzite
Kyanite
Labradorite
Larimar (Pectolite)
Manganotantalite
Mawsitsit
Moonstone
Nephrite
Obsidian
Oligoclase
Opal
Peridot
Pollucite
Prehnite
Pyrite

Rhodonite
Rubellite
Rutile
Scapolite
Scolecite
Sellaite
Sillimanite (Cat’s Eye)
Sinhalite
Sodalite
Sphalerite
Sphene
Spinel
Spodumene
Star Diopside
Star Sunstone
Staurolite
Sunstone
Tigers Eye
Topaz (White)
Tourmaline (Cats Eye)
Tsavorite
Unakite
Vesuvianite
Wilsonite

Gemstones Which Are Usually Treated & How

Gemstone

Treatment

Explanation

AGATE

Dyed or Heated

Used to alter color, these treatments are usually applied.

AMAZONITE

Colorless Wax, Oil or Hardened Resin.

	Used to improve the gems’ appearance, these treatments are usually applied.

AMETHYST

Heated

	Used to lighten color and/or to remove smokiness, this treatment is only occasionally applied.

AQUAMARINE

Heated

	Used to remove yellow components to produce a purer blue color with fewer yellow/green undertones this treatment is occasionally applied.

CITRINE

Heated

	Usually applied, this treatment produces color.

DIAMOND (COLOR ENHANCED)

The process known as Color Enhancement involves using clean Diamonds and modifying their color with a combination of electron bombardment and heat using safe electron-accelerator technology. Diamonds subjected to this treatment do not become radioactive. This process exactly duplicates the natural exposure of Diamond crystals to radioactive elements during their formation.

	Used to improve color intensity or to produce unique colors, this treatment is always applied for Color Enhanced Diamonds.

EMERALD

Colorless Oil or Polymers.

Usually applied, this treatment improves the appearance. If properly cared for this treatment is permanent.

JADE

Dyed

Rarely used, this treatment improves color and uniformity.

MORGANITE

Heated

Commonly used, this treatment eliminates yellow overtones.

MORGANITE (GREEN)

Cobalt Heated

	Always applied, this treatment induces vivid green color.

PEARL (CULTURED)

Bleached, Dyed or Chemically Enhanced.

	Occasionally used, these treatments improve color and uniformity.

PRASIOLITE (GREEN AMETHYST)

Heated

	This treatment improves color and appearance and is usually applied.

QUARTZ

Heated or Coated.

	Occasionally applied, this treatment improves color or produces unique colors.

RUBY

Heated Occasionally With Additives.

	Usually applied, this treatment produces, intensifies or lightens color and/or improves color uniformity and/or appearance. Examples of the additives used include Beryllium (i.e. light element) to permanently improve color and Borax or Lead (i.e. glass) to permanently improve appearance.

SAPPHIRE

Heated Occasionally With Additives.

	Usually applied, this treatment produces, intensifies or lightens color and/or improves color uniformity and/or appearance. Examples of the additives used include Beryllium (i.e. light element) to permanently improve color and Borax or Lead (i.e. glass) to permanently improve appearance.

TANZANITE

Heated

	Almost always applied, this treatment produces the violet-blue colors for which the gem is known.

TOPAZ (EXCEPT WHITE)

Heated, Coatings, Cobalt or Diffusion.

	Used to improve color intensity or to produce unique colors, this treatment is usually applied.

TOURMALINE

Heated

	Used to improve color intensity, this treatment is commonly utilized for blue green colors and only rarely applied for other color hues.

TURQUOISE

Epoxy Resin.

	Occasionally applied, this permanent treatment improves stability, durability, luster and/or color.

ZIRCON (BLUE & WHITE)

Heated

Used to improve color, this treatment is always applied.

Caring For Your Gemstones

*Unfortunately, most people overlook the proper care of their jewelry, resulting in unnecessary devaluation and loss of beauty.*

The Basics

For their protection, always remove your jewelry when engaging in activities that risk impact or exposure to chemicals (e.g. sports or housework). If you cannot remove your rings when using strong cleaning products (i.e. Ammonia based), protect your jewelry (and your skin) by wearing rubber gloves.

While rings and bracelets are most affected by daily wear, earrings, necklaces and even pendants are subject to chemical damage, especially if worn while make-up, fragrances and hair products are applied. Always put jewelry on after using cosmetics, hair spray or perfumes, not before!

Storing beaded necklaces flat is highly recommended to reduce stretching.

Try not to remove your jewelry by pulling on the gem. Apart from exposing them to sweat, oil and dirt, you also risk loosening their settings.

Always check for loose gems and clasps before wearing your jewelry.

To avoid your gems and metal jewelry scratching each other, never store your jewelry in piles. Store them in separate sections of a jewelry box or wrap them separately in velvet, paper or silk.

Carefully wipe jewelry with a soft chamois or flannel cloth after each wearing to remove oils and salts. This is especially important for Pearls.

Even the mild chemicals of commercial jewelry cleaning products may damage certain gems. A mild soap and water solution used with a soft brush is effective for many home jewelry care needs. Dry the jewelry with a lint-free towel.

If especially dirty it may be a good idea to take you Emerald jewelry to be professionally cleaned. As oils are occasionally used during the processing of Emeralds to fill inclusions, it may also be advisable to enquire whether they need to be re-oiled.

Mechanical Cleaners

These are devices that are typically used commercially to clean jewelry. The two most common are ultrasonic jewelry cleaners and steam cleaners.

An ultrasonic jewelry cleaner is an electronic device designed to remove dirt from jewelry. Ultrasonic jewelry cleaners feature two basic parts: a small motor and a cleaning tank. The machine’s motor produces ultrasonic energy which is transmitted with vibrating energy waves (usually 40,000 sound waves per second) that creates microscopic bubbles in the cleaning tank in a process called cavitation. The cavitation process knocks dirt off the jewelry. The motion is very effective at penetrating the tiny crevices in jewelry that traditional cleaning cloths and topical cleaners cannot easily reach.

A steam cleaner uses jets of steam to literally blast dirt off jewelry.

Some gemstones should not been cleaned using mechanical cleaners as the process will cause them damage. Below is a list of gemstones and whether or not they can be cleaned using mechanical cleaners:

Gemstone	Ultrasonic Jewelry Cleaner	Steam Cleaner
Alexandrite	Yes	Yes
Amethyst	Yes	Yes
Apatite	No	No
Aquamarine	No	Yes
Bixbite	No	No
Chrome Diopside	No	Yes
Chrysoberyl	No	Yes
Citrine	Yes	Yes
Danburite	Yes	Yes
Diamond	Yes	Yes
Druzy Titanium	Yes	No
Emerald	No	No
Epidote	Yes	Yes
Euclase	Yes	Yes
Fluorite	Yes	No
Garnet	Yes	Yes
Goshenite	No	Yes
Hiddenite	No	Yes
Idocrase	Yes	Yes
Iolite	No	Yes
Jade (Nephrite)	No	Yes
Jasper	No	Yes
Kunzite	No	No
Kyanite	No	No
Lapis Lazuli	No	Yes
Labradorite	Yes	Yes
Ruby	Yes	Yes
Malachite	No	Yes
Magnesite	Yes	Yes
Morganite	No	Yes
Mystic Topaz (Including Flamingo Topaz, Twilight Topaz, Cornish Blue Topaz, Moonlight Topaz, Canary Topaz, Kiwi Topaz & Neptune Topaz)	No	No
Natrolite	Yes	Yes
Opal	No	No
Peridot	Yes	Yes
Smoky Quartz	Yes	Yes
Sphalerite	Yes	Yes
Spinel	Yes	Yes
Spodumene	No	Yes
Rainbow Quartz	No	No
Tanzanite	No	Yes
Tektite	Yes	Yes
Topaz	No	Yes
Tourmaline	No	Yes
Tsavorite	Yes	Yes
Turquoise	No	Yes
Zircon	No	Yes

The AGTA Guide To Gemstone Treatments

*These symbols were set by the American Gem Trade Association (AGTA), to disclose any enhancements that may have been applied to gemstones. Gemstone sellers are encouraged to use these symbols when buying, displaying, and selling stone and stone-set jewelry.

Courtesy of “Rio Grande Gems and Findings”

ASBL Assembled from multiple layers or combinations of manufactured and/or natural material fused, bonded, or otherwise joined together to increase stability and/or imitate the appearance of a natural gemstone, create a unique design, or generate unusual color combinations. An example of this treatment is Opal Triplets.

B Bleached using heat, light, and/or other agents to lighten or remove color.

C Coating on the surface with such enhancements as lacquering, enameling, inking, foiling, or sputtering of films to improve appearance, provide color, or add other special effects.

D Dyed by the introduction of coloring matter to give a new color, intensify present color, or improve color uniformity.

F Filling of surface breaking cavities or fissures with colorless glass, plastic, solidified borax, or similar substances (visible under 10X magnification); improves durability, appearance, and/or adds weight.

H Heated to effect desired alterations of color, clarity, and/or phenomena. If residue of foreign substances in open fissures is visible under properly illuminated 10X magnification, “HF” should be used.

HP Heating and pressure combined to effect desired alterations of color, clarity, and/or phenomena.

IMIT Imitation product fabricated in such materials as glass, ceramic, or plastic designed to imitate or resemble the appearance, but not duplicate the characteristic properties of a natural gemstone.

L A laser and chemicals used to reach and alter inclusions in gemstones, usually diamonds.

O Oiling/resin infusion; the filling of surface breaking fissures with colorless oil, wax, resin, or other colorless substances, except glass or plastic, to improve the gemstone’s appearance.

R Irradiation using neutrons, gamma rays, beta particles, or high energy electrons to alter color. May be followed by a heating process.

S Stabilized using a colorless bonding agent (such as plastic); used on porous gemstones to add durability and improve appearance (sometimes referred to as “I” impregnated).

SYN Synthetic materials with essentially the same optical, physical, and chemical properties as a naturally occurring gemstone.

U Diffusion; chemicals used in conjunction with high temperatures to produce color and/or asterism (Cat’s Eye) producing inclusions.

W Waxing/oiling; impregnation of colorless wax, paraffin, and oil in porous, opaque, or translucent gemstones to improve appearance.

*The gemstones shown at the top of the page are (L to R): Apatite, Kunzite, & Ouro Verde.

**If the images and/or text on any of the web pages do not appear evenly spaced and centered on your screen, which commonly occurs with AOL pages, maximize the individual page's window. That should resolve the problem.