Carat . Colour . Clairty . Cut
CARAT WEIGHT
The "carat" is a unit of weight, it's divided into 100 points, therefore a "point" is a smaller unit of
weight, ( just like a pound is divided into 16 ounces) the point does not refer to anything else but
weight. Therefore a one carat diamond weighs 100 points and a 1/2 carat weighs 50 points or .50 carat
and so on. Carat weight is often referred to as size, diamonds are distributed based on their weight
and sorted into weight categories, for example a 1/4 carat weighs exactly 25 points, but diamonds that
weigh 24 to 29 points are priced in the quarter carat category, then you move up to thirds which
consist of diamonds 30 to 39 points, then forties, halves 49 to 59, sixties and then 3/4 caraters
70 - 79 points and so on to caraters which are at least 100 points. The price increases more and more
with each additional weight category (all other factors being the same) , for example, a one carat, good
cut, SI clarity, H colour, round diamond may be 15 to 20% more expensive than an identical stone weighing
just 99 points, (two different weight categories), just a one point difference can sometimes cost much
more!
COLOUR
Diamonds are found in a wide range of colours, but the overwhelming majority of diamonds used in the
jewellery industry are in the white range which encompass different shades of brown, gray or yellow.
Body colour of diamonds is rated from "D" which is colourless, to "Z" which is a light yellow that is
quite noticeable. Each letter represents a smaller range of colour, for example you can have a very
light "G" colour diamond and a darker "G" colour diamond as well, but both fall under the grade of "G".
The closer you get to a "D", the rarer a diamond is and therefore the more expensive the stone will be.
The colour of a diamond can only be graded accurately when the diamond is unmounted or "loose".
CLARITY
Most diamonds contain natural internal features called "inclusions" which were formed during the
crystallization process millions of years ago. It is the type, amount, size and position of inclusions
that determine the clarity grade of the diamond. The clarity grading system established by the G.I.A.
is as follows:
FL . flawless . No external or internal imperfections
IF . internally flawless . No internal inclusions
VVS1 - VVS2 . very, very slight inclusions
VS1 - VS2 . very slight inclusions
SI1 - SI2 . slight inclusions
I1 . eye one, inclusion barely visible to the trained naked eye
I2 - I3 . easy then obvious inclusions seen with the naked eye
Diamonds are graded for clarity only by an experienced professional using a 10 power magnification in
normal light.
Basically, from "SI2" all the way up to "Flawless" there are zero inclusions that you can see with the
naked eye and consequently any inclusions that are present WILL NOT affect the brilliancy of the stone.
Brilliancy is not really affected until you reach a clarity grade of I2.
I often described an "SI" clarity as a diamond which I could immediately see inclusions when viewed
under a ten power loupe, a "VS" clarity as a diamond that had inclusions that I had to look for,
while "VVS" stones had inclusions I literally had to search for. If the diamond is over 47 points,
these categories are always subgraded into one or two depending on the extent and position of the
inclusions. From this description you can easily see that clarity grading, ( as well as colour
grading), can be somewhat subjective. Therefore it is extremely important that the grading of a
diamond be done accurately and this is exactly why we sell only certified diamonds. When you order a
certified diamond you receive an unbiased grading certificate done by an experienced diamond expert in
the field of gemology using only the finest gem laboratory equipment available, therefore you can rest
assured that the characteristics of your diamond is properly graded.
"CUT" or "MAKE"
Simply put, the cut of a diamond determines both its brilliance (sparkle) and its dispersion
(rainbow effect of reflected light). The word "Cut", is also referred to in the jewellery industry as
the "Make" of a diamond, so as not to confuse "Cut" with the actual shape of the stone, e.g.. pear,
round, marquise, oval etc.
When we talk about the cut of a diamond we are referring mostly to its " proportions." When a diamond
is cut to good proportions, light is reflected from one facet to another and then dispersed through
the top of the stone, but when a diamond is cut too shallow or too deep, the internal reflected light
leaks out from the bottom of the stone, therefore the brilliancy is diminished.
Other factors that influence the cut grade are symmetry, finish, girdle and culet size. The grading
system used for cut is quite simple: #1 very good #2 good #3 medium #4 poor, subgrades such as "
medium - good " are also used.
|
|
