choose a stone…

choose a setting…

choose a metal…

choose a finish…

…choose ring

21 Meeting House Lane
Brighton
East Sussex
BN1 1HB

01273 773 544

choose a stone…

choose a setting…

choose a metal…

choose a finish…

…choose ring

21 Meeting House Lane
Brighton East Sussex
BN1 1HB
1273 773 544

21 Meeting House Lane
Brighton
East Sussex
BN1 1HB

01273 773 544

The 4 c’s of Diamonds – Part 3 of 5 – Clarity

Diamond
Clarity

Did you know that of all diamonds
unearthed from mines a mere 20% is destined for use in fine jewellery and of
them less than 1% is graded as flawless? Underground, during their
crystallization, and on their way up, diamonds trap mineral impurities. Extreme
pressure and heat often cause anomalies to their structure. These internal
characteristics are called inclusions. Nature or human hand can also cause
surface flaws; namely blemishes. Diamonds with the least visible defects
receive the highest clarity rates and the chilliest price tag. Before shopping
for the diamond of your dreams get to know what you are paying for. 
You may find our short video on Diamond grading helpful – click here to view.

History
of grading   

Clarity is one of the 4Cs of the diamond
grading system of GIA (Gemological Institute of America) that was established
in 1953 by the Richard T. Liddicoat team. Based on industry terminology and lastly
revised in the 1990s, the current scale consists of eleven clarity grades:
Flawless (FL), Internally Flawless (IF), Very Very Slightly Included 1 & 2
(VVSI & VVS2), Very Slightly Included 1 & 2 (VS1 & VS2), Slightly
Included 1 & 2 (SI1 & SI2), and Included 1-3 (I1-3). Today, each GIA
report for a-carat-and-over diamond contains its clarity plot or diagram which
is mapping its imperfections, and is used as a reference.

Types
of Imperfections

Inclusions are made of solids, liquids,
or gases. Beyond actual minerals in any form, they can also be structural
flaws. And they have interesting names such as pinpoints (tiny dot crystals), needles,
cavities, knots (dark and visible), clouds (a cluster of pinpoints or crystals
often causing haziness), feathers (internal cracks), and twinning wisps (a
visible mix of different forms of inclusions). Crystals within a diamond can be
white and blend in, while black carbon spots may be quite obvious. On the surface,
blemishes appear as man-made polish lines, scratches, and chips, or natural
nicks and pits (holes).   


Image courtesy of Cape Diamonds, South Africa.

The
Process

In the lab, the grader holds each
cleaned diamond in tweezers and examines it under a 10x magnification loupe with
darkfield illumination, from all angles as well as upside down, so that they
detect every possible inclusion through the table and the other facets. They
shift from darkfield to reflected overhead lighting to tell inclusions from
blemishes, and they zoom to the diamond via a stereo microscope (although
greater magnification doesn’t count in the overall grading). They also examine
it with naked eye from a 15cm distance and if they can’t see any inclusions
they describe it as ‘eye-clean’ (FL/IF, VVS 1, VVS2, and VS1). ‘IF’ diamonds
have only microscopic blemishes. Skilled graders find it very hard to trace
imperfections in the VVS ones and only a small percentage of VS2 are not
eye-clean. SI1/SI2 are rarely and I1-3 are never eye-clean. ‘Included’ are not
eligible for fine jewellery because their imperfections seriously affect the
brilliance, clarity, and often integrity of the stone.

Other
Factors

Inclusions visible under 10x
magnification affect the grading of a diamond but not necessarily its beauty
and desirability. In eye-clean diamonds you cannot see them. In those between
VS2 and SI1, your choice depends on various factors. The size and number of the
imperfections might lower the clarity grade. If a cloud is oriented in a way
that inhibits light transmission, the stone appears less charming too.
Inclusions located right under the top facet (table) or in the middle of the
crown are often noticeable. If found below the crown facets, they might pass
unnoticed. Inclusions near the edges or the pavilion might well be hidden by
the setting of a diamond ring. Yet relatively ‘sheer’ internal cracks close to
the surface might put the stone at risk of chipping or cracking. Finally, the
colour of an inclusion is mostly preferred to be white rather dark and
contrasting.

Shopping
Tips

The extremely few customers who shop for
flawless diamonds are willing to pay extra for the not-so-visible rarity of the
stone. In real terms, you can be equally mesmerized by a less rare VS2 which is
definitely value-for-money. Below that grade and up to SI1, everything should
be judged on a gem-by-gem basis. The size and the shape of the stone will also
define your choice. Opt for higher clarity grades in you need a larger or
step-cut (Emerald, Asscher etc.) diamond. Large or rectangular facets
especially those with a ‘mirror effect’ emphasize imperfections. Brilliant-cut
round, oval, princess, pear ones disguise imperfections via impressive
reflections.

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