II. Colored Gems
A. Treated Gems
1. Common Treatments
Two commonly accepted colored gem treatments are the oiling of emeralds and
the heat treatment of sapphires, rubies, and other colored gemstones.
(a) Oiling Emeralds
Nearly all natural emeralds have internal flaws or inclusions, due to the
turbulent environment in which they are formed. These flaws may break the
surface of the stones, and their appearance can be markedly enhanced by placing
them in a vacuum chamber and immersing them in cedarwood oil. The oil is
pulled into the minute spaces of the inclusions, making them less visually
apparent.
This treatment can produce a remarkable change in the appearance of an
emerald, greatly enhancing the beauty and color of the stone.
However, over time, or during improper cleaning, cedarwood oil can seep out
of the stone. It may be necessary to retreat the emerald periodically.
In recent years, several alternative filling materials have appeared on the
market. The most recent and more permanent is "Opticon."
(b) Heat Treating Colored Gemstones
Sapphires and rubies are often subjected to carefully controlled heat to
improve their transparency and color. Light blue topaz (often referred to as
"Swiss blue") is usually heat treated. Darker blue topaz (often
referred to as "London Blue" ) is sometimes heat treated and
irradiated (bombarded with very low doses of radiation) to enhance its color.
Tanzanite is always heat treated to bring out its wonderful violet blue hues.
Other heat treated stones include: aquamarine, tourmaline, citrine, amethyst,
and zircon. Heat treatment is a widely accepted trade practice, and results in
a permanent, stable color.
(c) Fracture Filling
As opposed to oiling (which has become an "industry-standard" practice),
fracture-filling of emeralds and glass-filling of rubies is a controversial,
yet also common, practice.
2. Disclosure: Your Right to Know
You may have heard of a recent lawsuit that arose over a treated emerald. The
NBC program "Dateline" reported on it. The case centered on whether treatment was
disclosed to the buyer of a $14,500.00 emerald and diamond ring. Apparently
Opticon was used to fill a large fracture in the stone. There's still debate
whether that filler was in the stone when the buyer initially took possession
of the ring, or was added later on (by another jeweler).
At Hight & Randall, Personal Jeweler, we always tell you about any
treatment or enhancement that your stone may have had. And you're fully
protected by our complete money back guarantee.
B. Synthetic Gemstones
Synthetic (or "created") gemstones are grown in a laboratory instead of being
formed in the ground by nature. They are physically, chemically, and optically
identical to natural-grown gems, but cost much less to produce and to buy.
Just like natural gems, synthetics vary tremendously in quality. Using
low-quality processes, synthetic emeralds and rubies can be created for less
than a dollar a carat, whereas high-quality (or "luxury") synthetics can cost a
hundred times more to create and sell for hundreds of dollars a carat.
Should you consider buying a synthetic gemstone? This is a difficult question
to answer. To some people, nothing can replace the magic of owning a beautiful
and unique product of nature. To others, what they see is most important.
Synthetics offer the opportunity to own an attractive stone at an affordable
price.
Many people believe a created gem is as "real" as one taken from the earth.
Still, quality is a major problem, particularly for lower-priced merchandise.
Here's a little background on synthetics, so you'll know the right questions
to ask.
You don't have to become an expert in synthetic gemstones, but it's important
to understand what you're buying. If the salesperson in the jewelry store can't
answer your questions (or find out from somebody else there -- quickly), then
you're in the wrong place to buy gemstones.
There are many different production methods used to create synthetic gems,
but they all fall under two major types: melt growth and solution growth.
1. Melt-Growth
Two common melt-growth methods are Verneuil flame fusion (or just "flame fusion")
and Czochralski pulled-growth. (Hope you're not falling asleep yet!)
(a) Flame Fusion
The first technology utilized for growing gemstones in a laboratory, flame
fusion, was first introduced in 1885, and is still very widely used to create
rubies, sapphires, and spinel. It's inexpensive, but yields low quality gems.
These created gems are often used in "class rings" and cheap jewelry found in
discount stores. It's relatively easy for any competent jeweler to detect
synthetics created by flame fusion methods because the "dripped" molten material
forms "curved striae" (a thin, narrow wave pattern) as it grows.
(b) Pulled-Growth
Czochralski pulled-growth is also commonly used to create rubies, sapphires,
and spinel. It's a more complex and costly method, and creates better gems than
flame fusion.
Still, both these methods yield gems of questionable quality. Because they use
very high temperatures, it is difficult for manufacturers to achieve uniform
color (particularly in rubies and blue sapphires). The mechanical action of
melting and reforming crystals introduces disparities in the gems, which
scatter light and give the stone a "dead" look -- like a piece of colored glass.
2. Solution-Growth
Some believe that solution growth leads to higher quality gems than
melt-growth. There are two common solution growth techniques: flux and
hydrothermal.
(a) Flux Method
In addition to creating the "big three" (emerald, ruby, and sapphire), the flux
method is used to grow spinel and alexandrite. (Natural alexandrite is
extremely rare and expensive, and much synthetic material is misrepresented and
sold as, "alexandrite.") The flux method uses a supersaturated
chemical bath to form the crystals. Flux Method or Flux Fusion -- not to be
confused with Flame Fusion -- creates the highest quality and most expensive
synthetic corundum (rubies and sapphires). The first ruby flux fusion was
introduced in 1891, sapphire in 1910, and emerald in 1938.
(b) Hydrothermal Method
High quality emerald, as well as the less common aquamarine, morganite, and
beryl, can be lab grown by the hydrothermal method. It uses a water solution at
very high temperature and pressure and takes several months to create a batch
of gems. That's one of the reasons higher quality created gems cost so much
more.
3. Misrepresented Synthetics
What's the difference between a synthetic gem and a fake? A true synthetic or
"created" gem has exactly the same optical, chemical, and physical properties as
the corresponding natural gem. Any variation in chemistry removes this
correspondence, and the gem cannot be legally called a true synthetic.
4. Simulants
Otherwise, it is known as a "simulant," a man-made gem that has an outward
appearance similar to a natural gem but is physically, chemically, and
optically different. A "fraud."
Only true synthetics can be labeled as such. The Federal Trade Commission
regulates this, and only allows a true synthetic to be described by the
following terms: Lab-grown, Laboratory-grown, Lab-created, and
Laboratory-created. The FTC also allows "trade names" to be used, such as
Chatham-Created or Gilson-Created. You may also see "Synthetic" or "Man-made" used
as descriptive terms.
Unfortunately, these designations can be used to label cheap flame-fusion
created gems as well as the much higher-quality solution-grown stones. As
always, be very wary of cheap no-name goods. If you can't determine the
pedigree of the stone, don't buy it!
Unlike synthetic diamonds, which are still quite rare, the market has seen lots
of substandard created emerald, ruby, sapphires, and purple amethyst. You're
much more likely to find these cheap synthetics in discount stores than your
local independent jewelry store.
Unfortunately, a number of gem merchants mislabel and misrepresent colored
stones to the buying public. As always, it is best to deal with a reputable
seller who will guarantee your purchase satisfaction.
At Hight & Randall, Personal Jeweler, we comply with all laws and
regulations governing gem labeling and disclosure. You'll know exactly what you
are buying, and will be fully informed about any treatments or enhancements
that have been applied to your gemstone.
5. Assembled Stones:
You may have seen the recent ABC "Prime Time Live" report on
mislabeled and misrepresented jewelry. Prime Time Live producers purchased
jewelry at major department stores, mass merchandisers, national chains, a
leased jewelry department in a major store, as well as one independent jeweler.
Some of the jewelry purchased contained "doublet" stones. Doublets
and triplets are known as assembled stones - essentially
"sandwiches." Opal doublets, for example, are formed using a slice
of natural opal material, cemented to a slice of black onyx background
material. Opal triplets are made of an acrylic top piece, opal, and black onyx
background.
Other assembled stones include: garnet and glass doublets, synthetic sapphire
and natural sapphire doublets, and jadeite triplets.
Assembled stones are very inexpensive to produce, and, if misrepresented or
undisclosed, can yield enormous profits to the seller.
It is important that your jeweler have the proper training and equipment to
identify these stones. A quality binocular microscope, as well as fiber optic
lighting, refractometer, polariscope, spectroscope, and special immersion
liquids are some of the essential tools of gemology.
Unfortunately, many jewelry sellers elect not to buy necessary gem lab
equipment, and become properly trained to fulfill the responsibility of their
role in business. Since you don't have to be licensed or tested to call
yourself a "jeweler," anyone who buys jewelry can sell jewelry.
Be sure that your jeweler is gemologically qualified to tell the difference
between natural, synthetic, simulant, and assembled stones.
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