|
Clarity Enhancements
Clarity refers to purity of a diamond, whether colorless or colored, a
clear gem appears uniformly brilliant and exhibits luster from all
angles and facets. Clarity strongly evaluates a diamond’s worth.
Fractures, generally called feathers due to feathery white appearance,
are the most common inclusions in diamond. Other common inclusions are
solid crystals of other materials like garnet. The size, color and
position of inclusions can reduce the diamond’s value even if it is good
in other gemological factors. In such a case, treating and enhancements
can be helpful in increasing the value of a diamond.
Laser Drilling
Diamond is combustible and therefore laser drilling techniques
selectively target and substantially reduce the visibility of fractured
part of the crystal and iron oxide stains within the fractures. Laser
drilling of diamonds started around mid 1980’s and I soften followed by
glass infilling.
This process requires use of an infrared laser( 1060 nm wavelength ) to
bore extremely fine holes ( less than 0.2 mm) to approach the inclusion.
To initiate the combustion by laser, a layer of amorphous carbon or
other energy absorbent material is applied to the diamond’s
surface before laser drilling can begin, as diamond is transparent to
the laser’s wavelength. The laser drills a small tubular passage to the
inclusion and the diamond is then immersed in sulphuric acid to dissolve
iron oxide stains in the crystal. This method is unfit for removing
impurities which are diamonds themselves, because diamond cannot react
with sulphuric acid. These bore holes are readily detected under a
microscope, and can be almost straight, but sometimes can be slightly
bent having a “wrinkled" appearance. In reflected light, these holes can
be seen as dark circles gapping the facets. The diamond material
destroyed during the drilling process thus replaced by glass using
fracture filling techniques.
Fracture filling
Due to the visibility of the drilled holes in the diamond, research
began for devising a method to fill up this visible flaw. Glass filling
is the common method used for filling up the fractures. The glass used
in filling these fractures is specially formulated having refractive
index approximating to that of diamond. This method was pioneered by Zvi
Yehuda of Ramat Gan in Israel, and Yahuda is now a brand name applied to
diamonds treated with this process and has changes little since its
origin. Another attempt in glass filling method was made by Koss &
Schechter, an Israel based firm. They used a halogen based glass but it
proved unsuccessful. The details of Yehuda’s process have been kept
secret, but the glass used for the method is believed to be lead ox
chloride glass. New York based firm, Dailies, also uses lead bismuth ox
chloride glass for fracture filling.
Though the glass is nearly having the same refractive index to that of
diamond, but is can still be detected by a trained gemologist under a
microscope. The visible features include surface reaching bore holes and
fractures in drilled diamond, air bubbles and flow lines within the
glass.
Flash Effect
Another feature that represents a treated diamond is flash effect, when
bright flashes of color are seen when the treated diamond is rotated,
ranging from blue to purple to an orange or yellow, depending upon the
lighting conditions. The flashes are most intense when the plane of view is
parallel to the fracture plane. The flash effect can be diminished in
strongly colored diamonds. For example the blue colored diamonds would not
let the blue flashes to be clearly seen, whereas the yellow and red parts
will be more visible. The color of the filling glass is also different from
that of the treated diamond. It may be yellowish to brownish which can
impact the color grade of the diamond after fracture filling and a diamond
may go down a color grade. Therefore, fracture filling is performed on large
diamonds. But diamonds having carat weight of 0.02 carats have been fracture
filled.
The fracture filling of a diamond is not desirable in industry as well
as public, as the glass has a very low melting point and therefore melts
out of the diamond under the heat of a jeweler’s torch! If the jeweler
is unaware of the treatment, the heat of torch can lead to degradation
of clarity, even shattering. The treated diamond if placed in an
ultrasonic cleaner may also not survive. Yehuda diamonds are therefore
warrantied for retreatment for any debasement of the glass filling.
GIA, and other major gemological labs do not issue certificates for
fracture-filled diamonds. Some labs which do certify these diamonds
provide the certificates regarding the original properties of the
diamond, before the treatment.
Color Enhancements
Coloring of a diamond is performed by three methods: Irradiation, Thin
Film application and High Temperature and High Pressure (HTHP). The
first two are able to just intensify a diamond color (off colored Cape
series stones). Some irradiation methods produce a thin skin of color,
therefore these methods are applied to already cut and polished
diamonds. But HTHP modifies and removes color and can be performed on
both cut and rough diamonds. Only certain diamonds are treatable by this
method. Irradiation and HTHP methods are almost permanent in effect
unlike thin film method. CIBJO demands disclosure of all color
enhancements performed on a diamond...
Read more...
Diamond Fluorescence
Fluorescence is the emission of bluish light emitted by
about one third of gem-quality diamonds when exposed to
long-wave ultraviolet light. The intensity may vary from
faint to very strong. Under normal lighting conditions,
this property of fluorescence is not detectable.
However, a naturally fluorescent diamond tends to emit a
soft colored glow when held under an ultraviolet lamp or
“black light". Fluorescence is not harmful to the
diamond or to the wearer....
Read more..
Diamond Ring Settings
Diamond ring settings vary as much as the diamonds and
many innovative and new designs are created everyday to beat
competition. The ring setting type is as important as a diamond as it
would decide the final appearance of a diamond as a jewel. The variety
and quality of ring settings varies from jeweler to jeweler. If one
seeks the best or wants something different, he/she needs to search more
than one jeweler and also see the available variety on the online
jewelry websites. Wedding and engagement rings are available in....
Read more..
How to Take Care of your Diamonds
Diamond requires periodical cleaning to retain its beauty and luster to
last for a lifetime. Through day to day activities, diamonds get smudged
and soiled. Even when they are not worn, they collect dust. Lotions,
soaps and natural skin oils, can cause development of a film of grime
over the gem and inhibits their brilliance. Diamonds require regular
cleaning so that maximum light can be reflected and refracted giving out
fiery brilliance....
Read more..
Buying Jewelry from Online (Internet) Stores
Internet has made the world a small place. Beautiful
jewelry from many countries and much more variety and
beauty ever imagined is available on online stores. If
you can get very good quality jewelry at lower prices
with more variety in designs, then online jewelry stores
are always a better choice. And this is true with many
renowned online jewelry websites! Online jewelry
buying.....
Read more...
Read about Diamond History, Diamond Facts..
A symbol of innocence, justice,
faith and strength, the diamond was believed to make its wearers
courageous and victorious over their enemies. When set in gold and worn
on the left side, it held the power to drive away nightmares and soothe
savage beasts. Diamonds were even thought to be so powerful that they
could stop lechery. Diamonds have lured and fascinated us....
Back to Diamond
Information Summary...
|
Diamond Clarity Enhancements
