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F A C
E T - N A T I O N |
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Ruby
Treatments |
Your Source of Information |
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The name ruby comes from the Latin word ruber, which means "red."
The most expensive ruby color is a deep, pure, vivid red. Stones a
little pinkish, purplish, or orangey red are also considered rubies,
but gem and jewelry professionals make careful distinctions between
ruby and pink, purple, or orange sapphire. (Ruby and sapphire are
both corundum varieties.) Ruby is the gem quality of the mineral
corundum, one of the most durable minerals which exists, a
crystalline form of aluminum oxide.
A little over 10 years ago, a new
find of Burma ruby entered the United States market from Mong Hsu.
It was later discovered the stones were heated and fracture-filled.
Although glass is often found in the Mong Hsu material, it is the
result of the healing of fractures after the material is heated with
borox and other chemicals. More recently, the new beryllium diffused
treatment process caused panic in the international markets after
that treatment was uncovered. It now appears another new treatment
method may be entering the marketplace. The new treatment is
essentially a Yehuda treatment for ruby that injects a high
refractive index glass into the fractures of ruby which visually
improves the clarity. |
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Treatments
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Treatment |
Purpose |
Stability |
Prevalence |
Detection |
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Heat |
Improves color and/or clarity appearance |
Stable unless the stone is heated to very high
temperatures |
Very Common; experts estimate that up to 95% of
stones undergo some sort of heat treatment |
May be detectable by a trained gemologist of
gemological laboratory.* Can be undetectable, but
assumed because of prevalence |
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Surface diffusion (heating to very high temperature
in the presence of a coloring agent) |
Creates a very shallow layer of red color in
colorless or light colored sapphire |
Stable under normal conditions, but the color layer
can be damaged or destroyed if the stone is
repolished or recut |
Occasional
Diffusion-treated red corundum should not be called
ruby |
Detectable by a trained gemologist or gemological
laboratory* |
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Fracture-filling with oil or epoxy resin |
Improves clarity appearance by hiding fractures.
Colored oil or resin also improves color appearance |
Fair. Heat and chemicals can damage or destroy the
filling. Oil will probably dry out or discolor in
time |
Occasional |
Detectable by a trained gemologist or gemological
laboratory* |
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Cavity-filling with epoxy resin or glass |
Improves clarity appearance by hiding cavities; adds
weight if the cavities are large |
Fair. Heat and chemicals can damage or destroy the
filling |
Common |
Detectable by a trained gemologist or gemological
laboratory* |
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When large quantities of low quality corundums were
recently found in Madagascar, treating these stones
became a high priority. No matter what the Thai
treaters did, the results were not impressive. When the
original treater removed the ceramic tiles in his oven
and cooked a new batch of corundum, he could not
reproduce the results! He went back to examine the old
ceramics from his furnace and discovered a small piece
of chrysoberyl was stuck in the hot-face. Of course,
the logical conclusion was the chrysoberyl was the
cause for the color altering treatment. Now the
treaters started cooking everything they could find with
beryllium. The process finally expanded to crushing
natural chrysoberyl crystals into powder with heat.
Ruby has a
hardness of 9 on the mohs scale, and usually has
excellent toughness. Stones with certain treatments or
large fractures or inclusions may be less durable.
Stability Heat can cause a change in color or clarity,
it can also damage or destroy fracture- and
cavity-fillings. Rubies are generally stable to light,
but bright lights can cause oil to leak or dry out.
Chemicals can harm fillings and remove oil; soldering
flux containing boron and firecoat made with boric acid
powder, will etch the surface of even untreated stones. |
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Ruby has been the world's most valued gemstone for thousands of
years. Ruby was said to be the most precious of the twelve stones
God created when he created all things and this "lord of gems" was
placed on Aaron's neck by God's command. The bible says that wisdom
is "more precious than rubies," that is to say very valuable indeed.
In the ancient language of Sanskrit, ruby is called ratnaraj, or
"king of precious stones" and ratnanayaka, "leader of precious
stones." |
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