Know Your Emerald

Know Your Emerald

by Erum Ali Qureshi

Common identification features of emerald are listed below along with those of its common synthetic stones, imitations and simulants. The information is intended to be a ready reference to give you a fair idea as to the identity of a gemstone on visual examination. Suggestions and queries from readers about the topic are encouraged.

Know your emerald

Common identification features of
emerald are listed below along with
those of its common synthetic
stones, imitations and simulants.
The information is intended to be a
ready reference to give you a fair
idea as to the identity of a
gemstone on visual examination.
Suggestions and queries from readers
about the topic are encouraged.

emerald

 

A synthetic emerald is an emerald
that is grown in a laboratory as
opposed to being formed under the
surface of the earth. There are many
methods to do this: Hydrothermal,
flux melt method etc. Emeralds grown
by each of these methods have
distinctive inclusions that help
gemologists identify them for what
they are.

Imitations or simulants are stones
that imitate emeralds. For example a
dyed green quartz, or green jadeite
or green glass. These are totally
different materials that imitate (or
pretend to be) an emerald. Their
physical and chemical properties too
are completely different from those
of an emerald. These can be easily
identified on the basis of standard
gemological tests that determine
their specific gravity, refractive
indices and absorption spectrum.
Trained and experienced gemologists,
jewelers and gemstone dealers may
even sometimes be able to identify
these on a thorough visual
examination of the stone.

Beryl

The Beryl family of gemstones
consists of emerald, aquamarine and
Morganite. Color is the one feature
that is most important in this
variety of gems. Emerald without
doubt is one of the most sought
after gems and the first clue to a
green stones identity will be its
color.

Hardness

Emeralds are particularly brittle
since it rates as 7 1/2 on the Moh’s
scale of hardness. Its luster is
vitreous which means that it will
have a shine but one that is
slightly subdued.

Natural and Synthetic emerald
inclusions

Almost all natural emeralds contain
inclusions and these are a sure-shot
way to identify the stones.
Sometimes the inclusions are so
typical that it may even be possible
to prove the country of
origin-though this practice is not
widely prevalent.

Natural emeralds from few
prominent locations may have the
following inclusions:

Inclusions Description Locality
Three-phase inclusions It is a liquid-filled
cavity containing a solid
crystal and a gas bubble
Columbia
Two-phase inclusion Liquid filled cavity
with a gas bubble
India
Tremolite needles Usually needle like
crystals or fiber-like
inclusions
Zimbabwe
Mica flakes Flaky inclusions Present in emeralds from
many localities
Actinolite crystals Rod-like segmented
inclusions
Present in emeralds from
many localities

Synthetic emeralds on the other
hand display flux droplets,
which are drop like inclusions
or wispy veil like inclusions
that appear twisted within
healed fractures. Emeralds grown
by the Hydrothermal method are
often inclusion-free but may
sometimes contain spiky
nail-head inclusions which as
the name suggests, look very
much like tiny nail-heads.

Emerald Pendant - Treated Emerald

In general a synthetic emerald
will be relatively cleaner (free
from inclusions) than a natural
stone. Natural stones will
almost always have cracks,
fissures, inclusions or small
chips owing to emerald’s brittle
nature though rare
well-preserved specimens are
known to be free of these
blemishes.

Another point to be noted here
is that synthetic emeralds are
emeralds chemically and
physically- the only difference
is that these were created in a
laboratory as opposed to under
the surface of the earth. It is
incorrect to refer to them as
‘fakes’ or imitations.

Treatment

Many emeralds for commercial
sale are treated with oil or
polymer resin to fill surface
reaching fractures or cracks and
fissures inherent in the stone.
This improves the color and
clarity albeit temporarily.
Indications of the stone being
oiled are stains on the parcel
paper or on your fingers as you
handle the stone.

Composite stones

Emerald doublets or triplets are
rampant on the market. These
consist of two pale colored
stones (glass base and synthetic
spinel top, or glass base and
colorless beryl or rock crystal
top) cemented with a layer of
green paste or foil. Such stones
when set are difficult to
detect. These are also known as
‘Soude emeralds’ and are easily
detected when immersed in water
and viewed side-ways.

In set stones, when viewed under
magnification it may be possible
to see gas bubbles trapped
between the layers.

Although there are myriad
possibilities for confusion with
other similar colored stones a
thorough examination under 10X
and experience go a long way in
identifying natural emerald from
synthetics, imitations or
simulants. However in order to
be absolutely sure it is
imperative the stone is checked
by a trained gemologist with the
right equipment.

Common gemological terms used
in this article

Moh’s scale
Moh’s scale is a scale depicting
hardness in solid substances.
Talc is the softest solid rating
1 on the scale and diamond the
hardest rating 10.

Luster
Luster refers to the surface
appearance of a gemstone.
‘Shine’ to the layman. Luster in
gemstones is described as
vitreous (glass like),
adamantine (like a diamond),
sub-adamantine, chalky, earthy,
waxy etc.

Flux melt and Hydrothermal
Manufacturing procedures for
synthetic emeralds


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