Mon, 13 Jan 2003

Hearts and Arrows Diamonds and The Basics of Diamond Cutting

You already learned that cut is the most important factor affecting the beauty of a diamond.



The
aim of this tutorial is to illustrate what it takes to achieve the
ultimate in cutting precision and perfection – super ideal cut Hearts
and Arrows diamonds.

 

by Whiteflash Inc.,
Manufacturer of “A Cut Above” Hearts and Arrows Diamonds

H&A Scope

 

The Parts of a Diamond

 

Before
we begin, let us use the following definition: A diamond is a crystal,
a prism that reflects light and disperses it. In other words this
prism’s facets are two way mirrors that:

1. Reflect light or

2. Allow light to pass through them.

 

The Cutting Process

The
rough diamond is prepared, sawed and the stone is brutted (made round).
First 4 then 8 main facets are placed on the pavilion and the crown,
and then the diamond is given its second cut again to make sure it is
as round as possible. (No diamond can be absolutely rounded because the
rough material has a hard side and a soft side).

Because of
diamond’s refractive index, the pavilion (bottom of the diamond that
comes to a point) needs to be cut at an exacting angle. If there is
some slight deviation from this angle, the diamond begins to leak light
and this affects the light return.

The relationship between the crown and pavilion is also very important. We will see this in detail later.

Diagrammatic scheme of how a diamond is cut from the rough to the polished

 

How the Hearts are Formed

A view of the hearts and arrows forming during the cutting process through the Hearts and Arrows viewer.

 

 

1. The main pavilion facets outlined and one heart highlighted in red.

2. The main pavilion facet reflects on the opposite side.

3. It
takes 4 facets to make one heart and one arrowhead on the pavilion and
an additional 2 upper girdle facets to finish up and square off the
tips of the rabbit ears of the heart.

4. This
takes a total of 6 different facets. to create 1 Heart,-( 2 main
pavilion facets and 2 Lower girdle facets and it is the 2 upper girdle
facets that square off the bottom of the heart shape.) See pic.4-A:
without upper girdle facets and pic. 4-B: with the upper girdle facets
in place. Note the squared off heart shape.

It
is the lower girdle facets that are also responsible for separating the
arrowhead from the heart. This is because of the difference between the
angles of the main pavilion and lower girdle facets. Therefore, if the physical symmetry
is out the slightest, the optical symmetry will be affected. We are not
referring here to meet point symmetry which is where the facet
junctions meet.

The labs grade symmetry according to meet point symmetry. The physical symmetry is made up of X,Y, and Z-axis which is what influences the optical symmetry. The optical symmetry will clearly show the physical symmetry being in or out of perfect harmony.

The
lack of optical symmetry will be seen very clearly when viewing the
diamond through the Hearts and Arrows viewer. It is easier to
camouflage errors in the formation of the arrows, but it is impossible
to hide any inconsistencies in the heart pattern. In forming the arrows
there are less facets to align so errors are more easily camouflaged,
whereas in the hearts there are 6 facets that complete each heart
shape, and the slightest deviation is easily noticed.

Arrow Effect in Diamonds

As
we have learned, the main pavilion facets are responsible for the
formation of the hearts and now you will see its effect in causing the
arrows pattern.

The shaft of the arrow is formed when one
main pavilion facet reflects on the opposite main pavilion facet. The
main crown facet allows a different view of the reflected main pavilion
facet thereby forming the arrowhead.

 

 

 

Grading The Hearts

 

Quick Guide

  • 8 equal uniformed symmetrical hearts.
  • 8 distinct symmetrical Hearts that separate from the Arrowheads above. If above is correct check the following.
  • Check if the hearts are split, measure length of heart then the length of the split.
  • Calculate the % of the length split, if it is greater than 8% and there are more than 2 of them IT FAILS.


In Detail and picture essay

1. First check to have 8 equal hearts and arrow heads.

They
must be equal in size and shape as seen in the picture “True Hearts”
Below you are shown a true set which are acceptable and a set Where the
hearts are not quiet equal in size, but more importantly the hearts
split in the cleft. This is a NO NO! (Not formed correctly this is the
most difficult case of all to determine if it is correct or not)

 

 

In
A1, A2 and A3 the heart is well defined the gap between the Arrowheads
is distinct and clear and the split at A3 is minimal versus F1, F2 and
especially F3 where this is the case

2. Calculating
the accuracy and Hearts you can measure the length as shown X_to_Y in
1a (A template tool can be used) say this is 10mm.Iif you see any
splits in the cleft this is measured and it can be no longer than 8% of
the total length of the heart as shown by Z to C in 2A if there are
more than2 hearts split at more than 8% then it will not make the grade
True Hearts, in addition the arrow head must separate from the actual
Heart

 

WHAT HEARTS SHOULD NOT LOOK LIKE

Here
are examples of hearts that do not make it and are easy to determine.
Simply because they are not equal and homogenous and the arrowhead and
hearts blend together in some cases.

 


Here
is a picture of an AGS0 cut AGS3706305 note that the hearts are
splitting we can call them Variable V’s, also the Arrows heads and
shafts are needle like and not straight and are broken up.

 

Checklist

  • 8 equal uniformed symmetrical hearts.
  • 8
    equal uniformed symmetrical distinct hearts that separate from the
    Arrowheads above. If above criteria is correct then check the
    following.
  • Check if the hearts are split, measure length of heart then the length of the split.
  • Calculate the % of the length split, if it is greater than 8% and there are more than 2 of them IT FAILS.


This can be done visually once a standard of proficiency has been attained.

 

Grading The Arrows

1. Each arrow (8) must be clearly visible with a shaft and a arrow head.

2. The 8 arrows shafts as well as heads have to be straight and in the right position.

3. The 8 arrow points must meet the girdle.

4. There must be total uniformity and balance.

Poorly formed arrows.

These
arrows seem to be okay, but they are not because, there is no
uniformity, not all the arrowheads reach the girdle and the shafts do
not line up straight with the arrowhead. Note the three arrows
indicating the misalignment.

 

Well-formed arrows.

 

Visual Appearance

The
Heart and Arrow pattern is analogous to all round stones, but if the
diamonds have not been polished with super symmetry and well within the
ideal parameters according to AGS standards, they will not be correctly
defined. In addition, they take on a different form, shape and size.

Here
is a comparative study of the patterning in stones. All the diamonds
depicted here are 0.90 cts in weight they range from 0 to 7 on the AGS
scale according to cut parameters.

 

Phony Hearts and Arrows Diamonds

Just
because a diamond is cut to ideal proportions with an AGS0 does not
mean that it will exhibit a crisp and true hearts and arrows pattern.
In addition to being ideal, the diamond has to have super symmetry –
where all the angles and facets have to be perfect.

Missing Hearts

Arrow heads or V-marks

Broken, split and different sized hearts, must be equal and uniform

No gaps between hearts and V-marks or arrow heads

Perfect Hearts

 

Missing Arrows

Poorly formed arrows no definition

Crooked shafts misshapen arrow heads

Missaligned arrow heads with shaft

Perfect Arrows

Stones
that do not conform to these standards cannot be called TRUE Hearts and
Arrows. There should be no variation in both the hearts and the arrow
patterns. Quality A, B, C or 1, 2, 3 do not exist. They are either TRUE
Hearts and Arrows diamonds or they are NOT. These standards need to be
maintained just as they have in Japan where the standard was set and I
believe all should maintain.

Diamond Measurements and Machinery

Today
Sarin and Ogi instruments are used to read and analyze measurements,
angles and percentages. This is not a method to indicate the perfection
of cutting. These machines show the perfection of the engineering in
the equipment and the maintenance of the equipment.

Today’s
cutting equipment is a lot more exacting. What is more important is
that the equipment is in good condition and that the cutting plate skyf
(pronounced skife like knife) and tang (tool to hold the diamond) are
true and level (Fig. 1b) with each other so that there is very little
deviation in the measurements when the stone is completed. The larger
the stone the more visible this deviation can possibly be.

Note
in Fig. 1a that the cutter can dial in the angle for the main pavilion
or crown angles for the process of blocking out the stone in 8 cut. As
you can see this is not entirely up to the cutter but also the
engineers from the maintenance dept.

The precision of the
cutter is really seen in the brillanteering (polishing on the lower
and upper girdle facets as well as the stars) of the stone. This is
where the craft comes into today’s diamond cutting world, the finishing
of the stone the upper and lower girdle facets (half’s) and the stars.
It is here where we have to rely entirely on the cutter for his mastery.

The
Sarin and Megascopes are not measuring all these other angles at
present, but the precision an consistency of these angles would reveal
how great the cutter is. One method which reveals this all is by
looking through the H&A scope at the hearts, one can see the
precision and consistency of the cutting.

The antithesis of
this is when a master diamond cutter swindles a stone, meaning he
recovers the maximum possible weight and makes a lively stone. The
angles; measurements and percentages will deviate by much on this
stone, compared to a superideal. The Sarin machine will not show this
mastery in the cutting but deviation yes. This machinery dose not prove
how perfectly the stone has been cut. There is still one simple method
above all the sophisticated MACHINERY and that’s the heart and arrow
scope. If the machinery were to measure no deviation in other words if
each angle was exactly the same one would view a diamond that would
look dull to the eye much like a tympani drum, if one plays it in the
center the sound is not good at all compared to when it is beat off to
the side.

 

Figure 1a Figure 1b Figure 1c

 

Conclusion

Conclusion

We found a careful balance must be maintained between

1. Angles (balance between Crown and Pavilion)

2. Consistency of Heart pattern (supersymmetry also known as optical symmetry)

3. Symmetry (external meet point symmetry)

4. Excellent or Ideal polish with very good luster


I believe this is what I set out to achieve when we produced the first A CUT ABOVE
diamond in 1998.

July 2001
Whiteflash

Whiteflash.com