diamond cuts : ideal, perfect, hearts & arrows - what's the difference

I am doing some research before getting a diamond ring for engagement.
Many commented than cuts is the most important of the 4Cs. For various
websites & newsgroup, people are using the terms such as ideal cut,
perfect cut and hearts & arrow symmetry.

I wish to find out if there is a distinction between ideal cut and
perfect cut. Do they mean the same thing? Also, if we say that a
diamond displays hearts & arrows, do we mean that it is an ideal cut
diamond?

Thanks in advance.

forget perfect cut, it's a new term...carries no weight - maybe it's onlya
marketing term


they say hearts arrows diaplays better fire because it's perfectly cut, etc
etc
when they say 'ideal' that means the proportions...it's ideal - nearly
perfect

one should forget about those terms.
if it looks nice - it looks nice, period.
don't dwelve too much on it.

i'd get the biggest si3, or clean i clarity diamond you could find/get

that's my two cents.






wrote in message
...
I am doing some research before getting a diamond ring for engagement.
Many commented than cuts is the most important of the 4Cs. For various
websites & newsgroup, people are using the terms such as ideal cut,
perfect cut and hearts & arrow symmetry.

I wish to find out if there is a distinction between ideal cut and
perfect cut. Do they mean the same thing? Also, if we say that a
diamond displays hearts & arrows, do we mean that it is an ideal cut
diamond?

Thanks in advance.

wrote:
I am doing some research before getting a diamond ring for engagement.
Many commented than cuts is the most important of the 4Cs.

I agree, that it is very important, because a large diamond, that is D
Flawless can be ruined by a bad cut, and an included stone that is small
can be made to look better than it is, by an excellent cutter. Under
certain condition certain inclusions can be hidden, depending on how the
stone is cut.

For various
websites & newsgroup, people are using the terms such as ideal cut,
perfect cut and hearts & arrow symmetry.

I wish to find out if there is a distinction between ideal cut and
perfect cut. Do they mean the same thing?

Yes, most of the time they do. And to confuse you a little bit more,
there are about 30 to 40 different "ideal cuts". To just name a couple,
the "Tolkovski ideal cut" is quite different from the "Eppler ideal cut"
diamond. Size of the table, expressed in a percentage of the stone
diameter, is different, angles are different, total height, crown
height, and pavilion height (all expressed in percentages of stone
diameter) are all different. And that's just two of them. I have a
list of all the different ones in my studio. If I remember I will bring
it home tomorrow and post it.

Also, if we say that a
diamond displays hearts & arrows, do we mean that it is an ideal cut
diamond?

Not necessarily, just one that has been examined using one particular
method. Or, it is an ideal cut by just one definition, but not by any
of the others.

To make a long story short. Get a stone (if it is a round one) with a
small table, i.e. between 53 and 56% A little bit larger is OK if other
conditions are met. Most definitely do not get a stone with a table
larger than 60%. Also do not get a stone with a thick girdle. Too much
weight goes into a thick girdle.

Buy a diamond with a GIA certificate. Do not buy a diamond with an EGL
certificate. Those certs are pretty much bogus. Everyone in the
industry knows this. If a jewelry store owner or manager tells you
something like "You can trust me.", take your money and run.

Abrasha
http://www.abrasha.com

Lawrence wrote:


i'd get the biggest si3, or clean i clarity diamond you could find/get

"SI 3" or "clean I" clarity. Boy, you really go for the quality don't you.

There is no such thing as "SI3" or "clean I"

The GIA clarity grading scale, which follows the international
convention of grading guidelines, is as follows:

IF, VVS1, VVS2, VS1, VS2, SI1, SI2, I1, I2, I3

see:
http://ist-socrates.berkeley.edu/~eps2/wisc/giadia.html and
http://www.preciousgemstones.com/giagradingreport.html

"SI3" is patent nonsense, it does not exist. "clean I" is even bigger
nonsense, in fact it is a contradiction in terms, because an I grade,
being at the very bottom of the clarity grade scale, means that it is
heavily included, so rather "unclean".

My advice , as I give all my clients who want to buy a diamond. By the
best quality diamond for your budget, eliminating the Flawless and VVS
grades, because those grades command a steep premium.


that's my two cents.


That's expensive, since I estimate your advice to be worth a great deal
less. It's just pain bad advice, since you don't seem to know what you
are talking about. I wonder if you are a professional in the jewelry
trade or someone giving his opinion.

Abrasha
http://www.abrasha.com

On Wed, 16 Nov 2005 08:01:29 -0800, in rec.crafts.jewelry Abrasha
wrote:


"SI3" is patent nonsense, it does not exist. "clean I" is even bigger
nonsense, in fact it is a contradiction in terms, because an I grade,
being at the very bottom of the clarity grade scale, means that it is
heavily included, so rather "unclean".

True, yet not quite. SI3 is indeed not at all a grade within the GIA grading
system. Yet some dealers have coined the term to describe those stones which
are rather on the borderline between the two grades. Some stones, if sent to
GIA, will come back with an I1 clarity grade, but who's inclusions, while
visible enough or significant enough to the durability of the stone to warrant
that grade, may still not make the stone unattractive to the naked eye ofthe
non-professional viewer. The I grades each encompass a rather broader range or
appearances than do the tighter finer grades above them.

SI3 is indeed, not an official grade, causes annoyance and angst among those of
us who prefer to use the GIA grades as GIA defined them. It's kind of like
someone coming up with a ruler having 14 inches in it, which they still call a
foot long, claiming those extra two inches are useful somehow to the definition.

Yet even so, the term does get used in the trade, especially by those without
formal gemological training, and including some diamond dealers, and at least
one of the less respected gem labs, as I recall...

It would be fine if they wanted to use that grade but made it clear they'd
defined a new set of definitions for their terms, but unfortunately, they've not
done that.

Now "Clean I1", I have no trouble with. I1 clarity is a slightly broad range,
usually defined as stones where inclusions are visible enough to see withthe
naked eye, in the face up position, OR where stones have inclusions that have a
significant effect of durability, even if not visible to the naked eye. If the
visibility can be described as "easily visible", then the grade drops to I2, but
"visible" has some leeway. Some are barely visible, just barely deserving the
I1 grade,and others only barely escape the I2 grade. Diamond grading is
subjective enough that looking for an I1 that's at the top of that range is a
reasonable thought, though hard to actually define on other than a stone by
stone, personal preference, level. Calling it a "clean I1" is indeed a somewhat
confusing term, as Abrasha rightly points out, But I at least, understood what
was meant...

Peter Rowe

Peter W.. Rowe, wrote:


Now "Clean I1", I have no trouble with.

He did not say "clean I1". He said "clean i"

I1 clarity is a slightly broad range,
usually defined as stones where inclusions are visible enough to see with the
naked eye, in the face up position,

Not "usually" defined as, but "always" defined as: "I1, I2, and I3 have
large inclusions that are visible to the naked eye."

See http://www.preciousgemstones.com/giagradingreport.html

OR where stones have inclusions that have a
significant effect of durability, even if not visible to the naked eye.

Where did you get this nonsense? "inclusions that have a significant
effect on durability"? Don't even bother to explain this one.

"even if not visible to the naked eye"? "I grade" stone inclusions are
ALWAYS visible to the naked eye, ... per definition. For the simple
reason, that they are large, and/or there are many of them.


If the
visibility can be described as "easily visible", then the grade drops to I2, but
"visible" has some leeway.

No there is no leeway. Visible to the naked eye as per definition of an
"I grade" is just that, nothing else. No room for leeway here.

Some are barely visible, just barely deserving the
I1 grade,and others only barely escape the I2 grade.

"I grade" stones never have inclusions that are "barely" visible. The
inclusions stick out like a sore thumb.

Adjectives like "easily" and "barely" are not used in grading diamonds,
and especially not when it comes to "I grades".

Inclusions in an "I grade" stone are always easily visible, because they
are large and in multiples. By definition inclusions in "I grade"
stones are visible to the naked eye.

Diamond grading is
subjective enough that looking for an I1 that's at the top of that range is a
reasonable thought, though hard to actually define on other than a stone by
stone, personal preference, level. Calling it a "clean I1" is indeed asomewhat
confusing term, as Abrasha rightly points out, But I at least, understood what
was meant...

Peter Rowe

Abrasha
http://www.abrasha.com

On Thu, 17 Nov 2005 08:07:28 -0800, in rec.crafts.jewelry Abrasha
wrote:

Peter W.. Rowe, wrote:


Now "Clean I1", I have no trouble with.

He did not say "clean I1". He said "clean i"

True enough. I said i had no trouble with "Clean I1", I didn't say I hadno
trouble with "clean i". However, I also had little trouble interpeting the
intent of his statement. I generally try not to hold peoples inexact spelling
in the way of comprehension. Sometimes, this is a mistake. This time, though,
I'm pretty sure I understood what he meant to say.


I1 clarity is a slightly broad range,
usually defined as stones where inclusions are visible enough to see with the
naked eye, in the face up position,

Not "usually" defined as, but "always" defined as: "I1, I2, and I3 have
large inclusions that are visible to the naked eye."

See http://www.preciousgemstones.com/giagradingreport.html

That's nice, but it's a general simplification, not an accurate or full quote
from GIA's definitions. Imperfect grades include stones where inclusionsare
visible to the unaided eye, and ALSO stones where inclusions, even if not
visible to the naked eye, post a significant threat to the durability of the
stone. But some stones with eye visible inclusions, even occasionaly inthe
face up position, may get better than an I grade. And some stones where
inclusions are not at all eye visible, may still deserve the lower I clarity
grades. Throwing words like "always" around in a field where the grades are
quite subject to the human decisions and opinions of the graders is risky
business.


OR where stones have inclusions that have a
significant effect of durability, even if not visible to the naked eye.

Where did you get this nonsense? "inclusions that have a significant
effect on durability"? Don't even bother to explain this one.

But I think I'd better. Youi're accusing me of nonsense here, and I suspect the
folks who designed the GIA grading system we use, and from whom I learned
diamond grading, might object. Some stones may have a cleavage extendingto the
surface in such a manner that, in the opinion of the grader, they would be
significantly easier to extend or otherwise contribute to damage occuringto the
stone which would not be the case in the absense of that cleavage. I can
recall, for example, marquise shaped diamonds with cleavages almost cutting off
one point of the stone, yet through some quirk of positioning and reflections,
impossible to see with the naked eye in the face up position. But I'm sure glad
I wasn't the poor sap who had to set that thing...

A bit of quoted definition text appears to be in order. This is quoted directly
from the GIA diamond grading coursework. From the "horses mouth", so to speak,
not a reinterpretation by someone else (such as your listed web site). This
copy happens to be a bit older, from 1986. But to the best of my knowledge,
they haven't changed these definitions.

"Slightly Inlcuded (SI1 and SI2)

These grades describe stones in which the inclusions are noticeable or fairly
easy to see under 10x magnification. Tyhpical charqacteristics include clouds,
included crystals, and feathers. None are visible when the stones are viewed
face up with the unaided eye, although they may sometimes be seen when the stone
is viewed through the pavilion.

Imperfect (I1, I2, and I3)

These grades included diamonds with inclusions which are obvious under 10x
magnification, or which can be seen with the unaided eye, and those that have
inclusions, such as large cleravages or large included crystals surrounded by
feathers, that seriously influence durability. " These grades also include
diamonds in which the inclusions are so numerous that they affect transparency
and brilliance.

The difference between I1, I2, and I3 diamonds are matters of degree." ....

.... and later on that page...

"A large stone with an eye-visible inclusion at or near the girdle may not
warrant an I grade, because the inclusions could be removed with much less loss
of value than an I grade would suggest. When appraising, some diamond experts
grade such stones as Is, but value them on the basis of the recut grade and
lower weight they would have if the inclusion were removed.
Inclusiions are often easier to see in large stones and in emerald cuts because
the facets are larger. If the inclusions are difficult to see with the unaided
eye, the diamonds are sometimes graded as SI."

And, not quoted from the GIA text, but I'd also mention that i've seen diamonds
which had no large individually visible inclusions, but which were suffused with
large enough but very faint clouds, that the whole stone then lacked as much
transparency as it should have. These look dingy and poor, and are clearly
Imperfect, yet you only can see the visual effect of the inclusions, not the
inclusions themselves. Some of these may require fairly significant
magnification before you can resolve the actual tiny inclusions that makeup the
clouds

The bottom line here is that diamond clarity grading is rather subjective.
Graders have to evaluate each stone individually. So far, attempts to precisely
quantify clarity grading to remove the subjective judgements of human graders
have proven difficult. This is part of why good labs like GIA don't always
assign a grade just on the opinion of just one grader, but rather, when needed,
on the collective opinions of several graders.

Remember too, that people's visual acutiy can vary, as does the visiblityof
inclusions depending on the cut and size of a stone, as well as the lighting
conditions. this latter can make an enormous difference. I've seen any number
of well graded VS clarity stones where, with the unaided eye, one could clearly
see the inclusions when an intense point source of light was directed at the
pavilion of the stone, almost paralell to the girdle, or slightly upwards.
That's an intensely contrasty lighting setup, even more so than the standard
dark field illuminators in gem microscoped, and with some stones, even very tiny
included crystals light up like little beacons. Take away the light, andtry
though you might, you can't see them. So does this lack of magnifcation mean
these were eye visible inclusions thus deserving of an imperfect clarity grade?
Of course not


\
\

"even if not visible to the naked eye"? "I grade" stone inclusions are
ALWAYS visible to the naked eye, ... per definition. For the simple
reason, that they are large, and/or there are many of them.


See above for the correct, full definition. Usually, of course, you are quite
correct. MOST imperfect grade stones will have eye visible inclusions. My
point is simply that this is not actually the precise definition in all cases.


If the
visibility can be described as "easily visible", then the grade dropsto I2, but
"visible" has some leeway.

No there is no leeway. Visible to the naked eye as per definition of an
"I grade" is just that, nothing else. No room for leeway here.

Of course there's leeway. Among other things, "visible" means to the human eye,
and there is some variability in human vision. Does "eye visible mean only to
the young eagle eyed 20 year olds who can see with better than 20/20 vision, or
to the 45 year old experienced diamond dealers who know the grades well but
maybe cannot see every tiny speck they once could? How 'bout the guy who's so
near sighted that he can hold a stone three inches from his eye and focus
clearly? That amounts to several power magnification in what he might beable
to resove, but is still, for him, naked eye. And the definition mentions
magnification (none for eye visible), but doesn't get into details such as
lighting conditions, beyond the general stuff like assuming a qualified and
trained observer. Lighting isn't specified, for example. And in this case, I
was referring to the inexact judgment between, for example, an inclusion that is
eye visible with some difficulty, versus one that's easily visible. Whendoes
the one stop and the other start? That's a subjective decision. Most graders,
with most stones, will agree pretty consistantly, due to lots of practice. But
there are always some stones that are simply borderline between grades, and
here, the decisions of what grade to assign can be quite unclear. Diamond
grading is as much art and skill, as it is science.


Some are barely visible, just barely deserving the
I1 grade,and others only barely escape the I2 grade.

"I grade" stones never have inclusions that are "barely" visible. The
inclusions stick out like a sore thumb.

Then I suspect you're grading some I1 stones as SI2, if you find inclusions that
are not quite visible enough to look like a sore thumb to you. Or that what you
consider sticking out like a sore thumb may not appear quite that obviousto all
other observers....


Adjectives like "easily" and "barely" are not used in grading diamonds,
and especially not when it comes to "I grades".


You may not find such words in the written definitions of a grade, but GIA
instructors will often use such adjectives when helping students to understand
just where divisions between one grade and another may be. The words are too
imprecise for a specific definition, but useful enough to help with
understanding the meaning of a given clarity grade.

Inclusions in an "I grade" stone are always easily visible, because they
are large and in multiples. By definition inclusions in "I grade"
stones are visible to the naked eye.

Nope. See above discussions. Can be single inclusions, even those not quite
eye visible, if of the right (or perhaps one should say, wrong...) type.


Diamond grading is
subjective enough that looking for an I1 that's at the top of that range is a
reasonable thought, though hard to actually define on other than a stone by
stone, personal preference, level. Calling it a "clean I1" is indeeda somewhat
confusing term, as Abrasha rightly points out, But I at least, understood what
was meant...

Peter Rowe

Abrasha
http://www.abrasha.com

Peter Rowe G.G.