Getting Started
"Beauty, durability and rarity; such
are the three cardinal virtues of a perfect
gemstone. Stones lacking any of them cannot
aspire to high place in the ranks of the
precious stones".
Dr. G.F. Herbert Smith (1872-1953), Gemstones
and their Distinctive Characters
Nicely put Dr. Smith, and when it came to gems
he certainly knew what he was talking about! As
a British mineralogist who worked for the
British Museum of Natural History, Dr. Smith was
responsible for developing the first efficient
jeweller's refractometer (an instrument used to
measure the refractive index of gems,
click here for more).
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My 'first contact'
with gemstones happened when I was about
10 years old. I still remember being
mesmerised by a small water-filled
container full of Opal tailings, given
to me by an aunt. My professional love
affair with gems started eight years ago
under the shadow of Khao Ploi Waen, 'the
mountain of gemstone rings' in
Thailand's Chanthaburi Province, an
international centre for coloured
gemstones. My first experience handling
gems was certainly anything but
illustrious - I shot a gem from my
tweezers, almost taking out a
colleague's eye! This book is written
for people looking for some beginners'
tips to clever gemstone buying and
appreciation. Hopefully, after reading
this book you'll love gemstones as much
as I do. Apart from personal experience
and published sources, a lot of the
information in this book comes from just
talking to people. Like any industry
dominated by passionate individuals,
opinionated discussions are commonplace
and always very enlightening. I would
also like to point out that the gem
industry is not full of villainous
scoundrels ready to deceive at the drop
of a hat. By and large, gemstone
traders, wholesalers and retailers are
qualified people looking to turn an
honest dollar. Just make sure you are
buying from a reputable seller. Look for
membership to trade organisations, such
as the ICA (International Coloured
Gemstone Association) and seek assurance
by getting your purchase independently
appraised (click
here for more). |
Mineral or organic materials (click
here for
more) worn for personal adornment, a gem is only
a gem when it is beautiful, durable and rare.
Occurring entirely by chance, gemstones truly
are amazing miracles of nature. While anyone can
appreciate the aesthetic beauty of gemstones,
even a basic understanding will make owning
gemstones much more rewarding.
In my experience, most people are far more
comfortable buying Diamonds than coloured gems,
and I guess this isn't surprising considering
the amount of money the Diamond industry has
spent on advertising. But when it comes to
coloured gemstones, most people are unsure
what's available, let alone how to determine
value. Sure, they might be able to rattle off a
few birthstones and some of the more well-known
varieties, but unless they or someone they know
is 'into' coloured gems, their knowledge barely
scratches the surface. This is a pity, because
it's easy to become a clever gem buyer. My
happiest 'eureka' moments are when people
discover they don't have to be millionaires to
enjoy coloured gemstones. Coloured gemstones
often give a 'big bang' of colour for a
reasonable price and many are actually rarer
than Diamonds.
Thanks to Diamonds, most people have at least a
fleeting recognition of the 4Cs (colour, cut,
clarity and carat weight). The 4Cs are a good
way to describe beauty in gemstones; they give
us an easy value guide to what initially seems
like very complicated territory. While the 4Cs
are a strong foundation, there are other factors
that also need to be considered when purchasing
gemstones. We'll cover these below, including
their relative importance and interrelationship
to a gemstone's final value.
World of Colour
It will come as no surprise that colour is the
single most important factor when assessing
coloured gems. As a percentage, it is estimated
that colour contributes to about 50 percent of a
gem's final value. Size (carat weight), cut and
clarity all directly impact a gemstone's colour.
Considering its importance, I've devoted an
entire section to colour
click here.
A Cut Above
One of the biggest misconceptions of 'cut' is
its importance to the overall value of a
gemstone. One popular book on gemstones states:
'The cut is subjective and may have little or no
effect on the buying price'. I disagree, ranking
'cut' as the second most important C. Why? Even
if a raw gemstone crystal has excellent colour,
poor cutting can negatively affect how this
colour is communicated to the eye in the
finished gem. Inversely, a raw crystal with an
average colour can be accentuated by good
cutting. Skilful cutting can also reduce the
impact of inclusions (see below) by placing them
in locations not immediately visible. Please do
not underestimate the importance of a gemstone's
cut. Much like colour, cutting is so important
that it has its own section, starting on
click here.
Bringing Clarity to Clarity
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Emerald showing its
characteristic
inclusions known as
'jardin' (garden)
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Most gemstones are crystalline and possess a
'crystal structure', a regular, repeating,
three-dimensional arrangement of bonded atoms.
The majority are comprised of a single crystal (s Amethyst, Sapphire and Tourmaline. Other
gems have a crystal structure that is so fine
that no distinct particles are recognisable,
even under the microscope. Termed
'cryptocrystalline', they include gems such as
Agate, Chalcedony and Jade.Regardless of
their crystal structure, very few gemstones grow
in nature undisturbed. The process of gemstone
formation is often cataclysmic, resulting in
tiny natural features called 'inclusions', which
are sometimes called 'flaws'. To me, this is as
inappropriate as calling the slight
imperfections in a silk jacket or the knots in a
wooden table 'flaws'. In my mind, they are
'natural characteristics', mother nature's
hallmarks of authenticity that record a gem's
natural relationship with the earth. Inclusions
are typically microscopic and most easily
glimpsed under magnification, either by using a
jeweller's loupe or microscope. A gemstone's
clarity is determined by the amount and location
of its inclusions, for example, eye-clean (no
visible inclusions when the gem is examined 6
inches from the naked eye), slightly included,
moderately included, heavily included, and
severely included. There are two general rules
of thumb regarding clarity:
- The higher the clarity grade, the higher
the value of the gem.
- Inclusions that don't interfere with the
brilliance, scintillation (sparkle) and fire
of a gem, do not affect its value.
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Blue Diamond, a 'classic' transparent gemstone |
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Agate, opaque but
still colourful
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However,
please be aware that attractive, characteristic
or interesting inclusions can add value to a
gemstone, for example asterism in Star Rubies (click
here and click here for more).
Related to clarity, but influenced by a
gemstone's chemical composition, crystal
structure and inclusions, different gems
inherently display different levels of opacity:
As you gain experience, you'll begin to
expect certain degrees of clarity from certain
gems. Some gem varieties always have more
inclusions than others. This is neither good nor
bad; it's just the way they are found in nature.
To make sense of these natural differences, the GIA (Gemmological Institute of America)
classifies gems into three types based on the
prevalence of inclusions:
- Type I: These gems grow extremely clean
in nature and usually have no eye-visible
inclusions, for example Aquamarine.
- Type II: These gems typically grow with
some minor inclusions in nature that may be
eye-visible, for example Ruby.
- Type III: These gems typically grow with
many inclusions in nature and they are
usually eye-visible, for example Emerald.
Not all gems have been 'type' classified by
the GIA, only the more prominent gems at the
time of developing the system. Translucent,
opaque and cabochon cut gems are not 'type'
classified. But whatever you do, please do not
incorrectly deduce that a Type III gemstone is
inherently inferior to a Type I gemstone.
Weighing In
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Seeds of the carob plant were used
during antiquity to weigh gemstones
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All things being equal, the bigger the gem,
the higher the value. In general, colour and/or
optical phenomena, such as colour change or play
of colour (click
here for more), is more
visible in larger gemstones.
Gemstones are traditionally weighed in carats (1
carat = 0.20 grammes/200 milligrammes). For
gemstones weighing less than 1 carat, their
weight is expressed in units that are 100 times
smaller, known as points (e.g. 50 points = 0.5
carats). Originating in the bazaars of the Far
East, where carob seeds were once used to weigh
gems, carat weight was standardised as one-fifth
of a gramme in Europe in 1907. But why did the
ancients use carob seeds to weigh gems? They
were selected because of their consistent size
and weight. Please don't confuse 'carats' with
'karats'. Karat measures gold purity and is only
related to 'carat' from the use of carob seeds
to weigh the alloys added to pure gold. In the
United Kingdom gem 'carat' weight and gold
'carat' purity are both confusingly spelt with a
'c'.
Bigger gems are always rarer than smaller ones.
A 4 carat gem is always worth far more than four
1 carat gems of the same quality. However, a
group of smaller gems will cost more than a
single gem of the same carat weight if the cost
to facet the individual gems outweighs the
difference in price. Due to their comparative
rarity, pairs or rows (suites) of matched gems
are more highly valued than single gems of the
same size and quality.
Passport Please!
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Ceylon Sapphire |
In my mind, the fifth C is 'country' of
origin. Much like brand names in sportswear,
gemstones with a historical pedigree rich in
legend and lore are times valued more
highly than gemstone's that don't have any
historical connotations. But this is not always
true, for example, the coveted Paraíba
Tourmaline was only discovered in 1989.
In a recent article in Coloured Stone magazine,
Editor-in-Chief David Federman says:
'Hallowed origins such as Kashmir and Mogok,
Burma, are pivotal value factors when pricing
Sapphires and Rubies that can make as much as a
40 percent difference in their value'. While
this might make sense if all things are equal
and the origin reliably certified, please
remember to use your eyes! Paying a premium for
an otherwise low quality gem simply because of
pedigree has always seemed absurd to me.
The country of origin never denotes quality;
good and bad qualities are found in every
deposit. Sure, some sources are noted for
producing more good quality gems than others,
making their origin quality indicative, but this
is never an absolute. For example, not all
Sapphires from Sri Lanka are of suitable quality
to warrant the 'Ceylon' moniker. For me, origin
is a collectable curiosity, an interesting
attribute that definitely adds to the appeal of
gemstones, but not something that is going to
make me want to own a gem I don't find
attractive.
While including names of geographical locations
should only be done when they denote the areas
from which gemstones originate, under CIBJO
guidelines (click
here for more) origin is
considered a matter of opinion.
It's a Small World After All
Let's face it, people are becoming
increasingly well-informed about global social
and environmental issues and in my mind, this is
definitely a good thing. At the end of the day,
gemstones are pure emotion, and the last thing
anyone wants to feel are negative emotions
associated with the suffering of others.
Accordingly, the sixth C is the 'confidence'
that comes from knowing your gems are from
legitimate sources not involved in funding
conflict or terrorism. With respect to Diamonds,
this is largely a given thanks to United Nations
resolutions and the Kimberley Process (www.diamondfacts.org).
With coloured gemstones, always check with the
seller.
Are You Tough Enough?
With proper care all gemstone jewellery
should be suitable for passing down through many
generations (click
here for more). Durability
is a combination of three properties:
- Hardness is the ability of a gem
to resist surface scratching (Mohs' Hardness
Scale). click
here for more.
- Toughness is the ability of a
gem to resist the development of fractures
(random non-directional breakage) or
cleavage (splitting along well-defined
planes). Please note that toughness and
hardness in gemstones can be mutually
exclusive. Just because a gemstone is hard,
it is not necessarily tough and vice versa.
- Stability is the ability of a
gem to resist physical or chemical damage.
All Gems Are Rare...
By their very definition all gems are rare,
but just like in George Orwell's 'Animal Farm',
some gems are rarer than others. When buying
gems always try to understand why a gem is
'rare', failing to do so makes it lose
relevance, becoming a throwaway term. I always
cringe when I hear jewellery salespeople
endlessly rabbit on about 'rarity' without any
contextual qualification. If rarity is worth
mentioning, it is certainly worth qualifying.
For example, Tanzanite is 1,000 times rarer than
Diamonds.
Rarity can be described in three, often
unrelated, ways: geological, marketplace and
comparative. Just because a gem is geologically
rare, this doesn't always mean it has a higher
value in the marketplace and vice versa. Beauty,
marketing and name recognition also play a big
part. Just look at Diamonds. Rarity can also be
a double-edged sword, sometimes it jeopardises a
gem's commercial viability, for example
Tsavorite.
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Just as nobody in
their right mind would call their loved
one 'semi beautiful', why oh why, do
people still call some gemstones 'semi
precious'? Derived from the French
'pierres precieuse', the traditional
'precious gems' are Emerald, Diamond,
Ruby and Sapphire. When other gemstone
varieties gained popularity they also
needed a name. For some reason, the
industry settled on 'semi precious' and
has regretted it ever since. Today,
'semi precious' is regarded as out of
date and misleading. This is because it
undersells these gems and is no longer a
true expression of value. For example,
some Rubies can sell for less than $100
per carat, while a fine Paraíba
Tourmaline can sell for over $30,000 per
carat. That seems pretty precious to me! |
Nip and Tuck
To make sure each gemstone reaches its full
potential, lapidaries and jewellers employ a
variety of techniques. Some of these, like
cutting and setting, are immediately visible,
while others, such as enhancements or
treatments, remain relatively unknown despite
being used for thousands of years. Visit
click here to learn about acceptable enhancements
applied to each gem variety, their frequency,
and any special care instructions.
Can You See What I See?
When you gaze upon gemstones, what do you see?
The following are some important terms used to
describe a gem's visual appearance as it
interacts with light:
- Lustre is the amount of light
that is reflected from a gem's surface.
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Onyx showing its
characteristic lustre |
- Adamantine is the very bright and
reflective lustre displayed by Diamonds. It
is derived
from the Greek root word for Diamonds 'adamas',
meaning 'unconquerable', which
is certainly appropriate for the world's
hardest natural substance! Sub-adamantine is
occasionally used to describe gems with a
lustre close to Diamond, such as Alexandrite
and Demantoid. While there are other
mineralogical terms to describe lustre,
these have
been omitted because they are of little
importance to your everyday appreciation of
gemstones.
- Scintillation is the play of
light (reflections from a polished surface)
that causes a gem to
sparkle as its relative position to either
the viewer or the source of illumination
changes.
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Incredibly rare and
brilliant, this is the only Vanadium
Chrysoberyl the author has ever seen |
- Brilliance is the amount of light
(i.e. body colour) that is reflected from a
gem's interior. Brilliance is dependant on a
gem's optical properties (click
here for more), cutting (critical
angle), colour, transparency, clarity,
polish, lustre and wear.
- Fire, also known as dispersion,
is the splitting of light into its component
colours. This
gemmological feature adds both beauty and
value. While all gemstones of a large size
exhibit fire, the most dispersive gemstones
ranked in order are Sphene1, Demantoid2,
Diamond3 and Zircon4.
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Diamond showing
its characteristic fire |
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