Diamond Jewelry King » jeweler

Diamond

King of diam — Mon, 21 Sep 2009 22:18:10 +0000

For thousands of years diamonds have been a form of decoration, currency and investment medium. Diamonds have risen in price over the years fairly consistently with inflation. At some points investment in the right stone would have returned a much better percentage than similar amounts of stocks, bonds or gold. On the other hand, an investment in the wrong thing or an investment made blindly because of lack of knowledge, can and in many cases has caused the buyer to actually lose money.

Remember, diamonds are normally sold on a retail basis. This is where you, the consumer, buy most stones. As one purchases stones of a higher quality and larger weight, stones that are designed for investment purposes rather than ornamentation, it is possible to actually buy at or near wholesale prices. When one goes to sell the stone, if one simply walks into a jeweler or New York-type diamond seller, one expects to lose from the retail price the stone may have been purchased at.

A number of factors establish the value of a diamond, one of which is the size of the stone. There are certain levels where the value of a high grade stone jumps appreciably simply because the stone is over this weight. In general, a large high-rated stone is worth logarithmically more than a number of small stones equaling the larger stone’s weight. It is, as one would expect, considerably harder to find flawless or near flawless large stones.

When the jeweler or professional goes to buy a stone there are several things he will evaluate in order. Generally the stone is graded using the four C’s of diamond grading. These are:

1. Clarity

2. Color

3. Cut

4. Carat weight

There are established methods and models for grading stones and one could reasonably expect to take a stone of a certain grade from one professional to another and come out with a similar rating. One should also remember this grading is subjective and there will be times when two accredited gemologists will give a different rating, possibly affecting the stone’s value, by hundreds or thousands of dollars to the very same stone. It is wise to be able to at least make a good amateur estimate of the various rating points on your own instead of having to blindly depend on someone you may not know.

Cut grading diamond

King of diam — Sat, 19 Sep 2009 22:15:55 +0000

Bear in mind also that a good diamond cutter can cut a colored stone in order
to make it appear whiter than it is WHEN THE STONE IS MOUNTED by doing a
shallower cut that’s more spread on the point where the facets come together.
This will make the stone appear less yellow, again only after it’s mounted.
This is another reason one should never judge a stone that is in a mounting
of any sort.
The cut of a brilliant diamond may be the most singular important consideration
in buying a stone within a set price range. Unless one is an expert and feels
his knowledge is good enough to override general public consideration, there
is only one cut to consider and that is the “brilliant” cut. Brilliant cut is
a modern cut that is a completely round stone designed with 58 facets to
maximize light reflection and “fire” within a diamond.
There are a lot of stones still around which have what is known as a European
cut. This cut was done in the 1920′s and before and does not compare in value
to the modern brilliant cut. The old cut or European cut stones were cut
before exact ratios and angles were established and understood by the gem
cutting society and, as such, do not maximize the reflecting and refraction
qualities of the stone. European cut stones such as those purchased at pawn
shops and estate sales, are much harder to resell and do not offer the
liquidity of a brilliant cut diamond.
There are other popular modern cuts such as the marquise, the oval and the
pear which attract some buyers when designed for jewelry, due to their unique
appearance. These cuts do not reflect as well as the brilliant cut and are
rarely seen in investment quality jewelry. Again, the fancier cuts will be
on the average much harder to sell (definitely harder to sell to a dealer)
than is the round brilliant cut stone.
Fancy cut diamonds have fewer angles cut to what is known as the “critical
angle” and, as such, cannot be as brilliant as a round cut stone. The fancier
a stone is, the more it differs from a brilliant cut, the greater the loss in
light reflection will be.
Another phenomena to be aware of in fancy cut stones such as pear shapes or
marquise shapes, is something called the bow tie effect. This is a dark,
cloudy area across the upper portion of the table on these stones. It is a
quality inherent in the cutting and looks like a cloudy bow tie across the
reflecting portion of the table. This obviously lowers the value of the stone
considerably and, if one is thinking about a fancy cut stone, this effect
should be taken into consideration.
Fancy cut stones have only two bottom facets as opposed to the eight found in
round cut stones to reflect the light back. While they still may appear to be
fairly brilliant, the refraction, the fire of the stone, will suffer
critically. This loss progresses from the marquise cut through the straight
cuts such as the emerald cut diamond. These straight cut stones suffer a great
light and fire loss and are not nearly as valuable as the same stone would be
cut in a brilliant cut.
An uncut diamond is normally sawn or split into two or more stones as decided
by the diamond cutter. It just takes a simple error here to completely ruin a
valuable stone and turn it into nothing but dust. Now you can understand the
hypertension rate among diamond cutters and airport controllers…
Once a rough diamond is split, the diamond cutter then decides how the stone
will be laid out and cut. This operation means that a certain portion of the
diamond will be ground off and lost and so this cut plan becomes an important
step in finishing the final stone.
The first step taken by the diamond cutter is to girdle the diamond. This
process of girdling establishes the size of the stone and puts a “waste” on
the stone (see the diagram). If a stone is poorly girdled, it will not appear
completely round when viewed with the jeweler’s loupe or microscope. A round
brilliant cut stone should be perfectly round and symmetrical.
Other mistakes in girdling will produce flaws that manifest themselves as a
razor thin girdle which is prone to chipping or breaking (even though diamonds
are extremely hard, they are brittle and can be chipped or shattered in thin
areas). A too thick girdle takes away from the brilliance and fire of a stone
and indicates a poor job on the part of the diamond cutter.
A diamond cutter cuts (in a brilliant cut) 58 facets all done on exact angles
in exact positions in order to let the diamond reflect as much light as is
physically possible. The brilliant cut stone has 16 facets on top and 16
facets on the bottom that reflect the light and give the stone its cut. Each
facet is cut on a unique angle and is exactly straight when viewed with other
facets in order to maximize light reflection.
When you view a brilliant cut stone, around the table of the stone you’ll see
the kite and the topmain facets. These facets are the areas that allow the
light to come through to the viewer. Beneath these you have eight star facets
and then 16 upper girdle facets before you reach the girdle itself. Beneath
the girdle you have an additional 16 lower girdle facets. All these ancillary
facets contribute to the light reflection through the kite and top main facets
and the table portion of the stone.
What is the advantage of the 58 facet brilliant cut stone? What does one
expect to see when viewing a diamond? There are two qualities that make a
diamond attractive to the eye. The first one is known as life and indicates
the amount of light that is reflected back from the diamond to the viewer.
The second quality is known as fire, which is an indication of the amount of
refraction from the facets and split into colors as in a prism effect.
Besides the 58 facets, a number of other factors contribute to the perfectness
of a brilliant cut stone. The stone’s table should be 53% of the area of the
stone. While the ratio between the depth of the stone or the length of the
stone if you view it from the side, to the spread of the stone which is the
maximum diameter of the girdle, this ratio should be 60% depth to spread.
The angles on a stone must be cut exactly to critical angles. Any deviation
will produce a less than perfect reflection of the light waves entering the
stone. A jeweler will have special gauges to measure these angles. These
gauges are available but they are expensive. Or one can buy a loupe that is
marked with angle markings.
When angles are viewed through this loupe, they can be accurately measured .
The first measurement to take is the degree of the angle from the table to the
girdle of the stone. This is known as the top critical angle and should be 34
1/2 degrees. Underneath the girdle, the bottom angle from the girdle to the
point of the stone is also a critical angle and should be cut at 40 3/4
degrees. A further measurement is that the girdle should be about 1% as thick
as the diameter of the stone, although this is not quite as critical as the
other measurements and can be judged by the eye after a bit of practice.
A stone which is not cut with the critical angles in the right degree, will
either be shallow cut or deep cut and will not reflect the light back through
the center of the stone (the table of the stone) with the same brilliance as
a stone that is cut to the correct angles.
If the stone is shallow cut, the light will reflect off the edges of the stone
but not through the middle. If it is cut too deeply, the center of the stone
will appear to be dark and it is called “heavy.” In the past some cutters cut
the upper angles at a less than 30 degree cut. This “spread cut” helps hide
deficiencies in a stone but makes the girdle angles sharp and likely to be
broken or chipped and the stone is not as valuable as a normally cut stone.
If the correct tool for sizing angles is not available, one can estimate that
if the table appears to be larger than it should, and the width to height
(that is the depth spread ratio) is below 60%, one can assume that the
critical crown angles are shallow.
It is possible to polish a diamond to a high degree to compensate for shallow
or deep cut angles at first glance and make the stone appear to be more
brilliant than it, in fact, is. If the stone is chosen for investment quality,
a measurement of these angles is almost essential .

Clarity of diamonds

King of diam — Sat, 19 Sep 2009 22:03:20 +0000

The first C is clarity. This is not the most important but is generally the
first item looked at in a stone to be rated. Clarity does not refer to the
concept of “being clear” with reference to a diamond. Clarity refers to the
purity of the stone and lack of visible defects.
These defects or flaws or as they are properly known, inclusions, may manifest
themselves as dark, black carbon spots, white carbon spots, small cracks,
“clouds”, feathers, or other areas of visible diffusion within a diamond or on
the surface of the stone itself.
A truly flawless stone, one without any spots, cracks or inclusions, is very
rare and extremely valuable. One can expect to find some flaws in most stones.
The type of flaws, size of flaws, and location will have an effect upon the
stone’s value. It is important to learn how to judge a stone for clarity.
The Gemological Institute of America (GIA) has established a rating system for
expressing the clarity of a particular stone. This rating system is based on
the use of initials and numbers and goes on a one to 10 oriented system
wherein 10 would be the best stone and one would be the worst stone.
This system is not expressed in simple numbers but with words and initials to
further establish the rating scale. The scale is as follows:

10 – Flawless – no blemishes can be found.

9 – VVS-1 – no flaws inside the table. Possible very small internal
flaws outside the table. If any external flaws are present,
must be very minor.

8 – VVS-2 – very difficult to see flaws with 1 0x magnification power
employed.

7 – VS – 1 – flaws readily seen using 1 0x glass but almost impossible
to see when the stone is viewed from from the back.

6 – VS – 2 – the back looking down through the stone.

5 – Sl – 1 – flaws unable to be seen with the naked eyes but quite
apparent using 1 0x magnification.

4 – Sl – 2 – inclusion may include carbon spots or clouds or feathers
underneath the table or larger flaws outside of the table.

3-1 – I-1 to 3 – this is the least valuable group. They are heavily flawed
and the flaws can be determined with the naked eyes. There
are going to be internal flaws inside the table, maybe
clouds, groups of carbon spots, feathers and/or cracks
that can be seen with the eye.

VVS – Very, very, slightly imperfect
VS – Very slightly imperfect
Sl – Slightly imperfect
I – Imperfect

A flawless stone is simply that. No flaw can be found even with the use of a
10x jeweler’s loupe or 10x microscope. As you go down the scale, the VVS-1 may
have one very small inclusion, generally not in the table (which I’ll cover it
later in the file) portion of the diamond but possibly on the edge. Again,
this flaw is seen only from the front and only on using 10x magnification. It
should not be visible to the naked eye.
As we get into VVS-2, there may be more than one flaw wlth magnification but
they’re still extremely small. One small inclusion may be in the table area of
the diamond.
Into the VS grades, the flaws become larger and more prominent than their VVS
cousins. VS2 may have larger flaws or a number of small spots possibly located
in the table of the diamond that group together and are almost considered one
flaw. They are generally in the same area.
When we talk about 10x magnification, this can be in the form of a jeweler’s
loupe which is a fairly inexpensive must-have item for anyone serious about
stones or a step upward which is the two eyepiece (stereo) microscope, which
many jewelers will have on the premises and will let one borrow when perusing
their stones.
It is wise to always make sure that the magnification device employed is 1Ox.
This is the standard and any variation from this will affect the rating of the
stone to a great degree.
Note that flawless VVS and VS rated stones are rated when looking at the stone
right side up with a 1 Ox magnification device. If you pick up a stone that
supposedly falls under one of these ratings and you can see inclusions with
the naked eye, you’re not looking at a stone that is properly rated.
An Sl-1 rated stone will have inclusions that are very obvious under 1Ox
magnification, but should still be borderline visible or not visible when
viewed with the naked eye. The Sl-1 stone may have these borderline visible,
small dots or inclusions in the table or edge of the stone. An Sl-2 rating
will have larger flaws and probably more than one. These will be easily
visible to the naked eye.
In the I grades, the stones can be considered either quite flawed or imperfect.
Flaws are probably inside the table. There may be flaws of more than one
variety, clouds, cracks or groups of black or white carbon spots will be
visible. This last group of stones obviously are the least valuable and the
least interesting for anyone trying to convert from cash to gems and back
again.
Looking backward we can infer several things, the first of which being if you
can spot a number of inclusions without the use of magnification device, the
stone is going to be graded 1, whether l-1, I-2 or l-3 is open to some
subjective effort, but it will be an I rated stone.
If you can’t find flaws with your eye alone but they do become visible when
using a loupe, one can assume that the stone is an Sl rated stone.
The differentiation between an S stone and a VS stone is that in a VS stone
inclusions may not be seen extremely clearly even with the loupe. If the stone
is turned over and laid on the flat front part (the face of the stone – this
is the table) and one views down from the back of the stone where all the
facets come to a point and the flaws are more readily seen here, one can
assume it is a VS-2 or above rated stone.
Note this viewing is done under white light and with the stone loose. It is
very difficult to judge any of the 4 C’s when the stone is mounted. Mounted
stones are not generally considered for investment grade purchases. The stone
should be loose and one should be able to turn it freely.