Hearts & Arrows Formation and Grading
In April 2004 Brian Gavin of Whiteflash.com
presented his grading system for Hearts & Arrows optical symmetry at the First
International Diamond Cut Conference in Moscow, Russia. It was hoped that
laboratories and peers would unite to maintain higher standards for manufacture
of diamond sold as "Hearts & Arrows." Though laboratories do not offer a grade
for Hearts & Arrows, Whiteflash does, and safeguards buyers of the 'A Cut Above'
brand with a guarantee of optical symmetry meeting the IDCC presentation
criteria. - Here is Brian's presentation on the Formation of Hearts and
Arrows
How the Hearts are Formed
Below are views of Hearts & Arows being forming during the cutting process as
they would be seen through a regular Hearts & Arrows Viewer. The leftmost
photos show the diamond blocked in 8. The center pair shows the pavilion fully
cut, with crown still in 8. The pair on the right show the fully formed Hearts
& Arrows when pavilion and crown have both been finished.
Overlapping Reflections
The graphic below shows, in sequence, how the main pavilion angles reflect to
create the heart pattern. One pavilion facet creates two opposite sides of a
heart. Two Pavilion facets create 1 heart and 2 single sides of the next heart
and so on until all the hearts are complete. Understand that these reflections
must overlap precisely for 8 hearts to appear.
Outside the Viewer
This picture shows the main pavilion facets outlined and one heart
highlighted in red.
The main pavilion facet reflects on the opposite side, and the lower girdle
half separates the arrowhead above the heart.
The Role of the Star Facets
Star facets square off the ends of the heart.
1: Without Star facet not in place and
2: With the Star facet in place. Note the squared off heart shape.
The Role of the Upper Girdle Facets
The upper girdle facets complete the patterning around the circumference of
the pavilion.
3: Without upper girdle facets and
4: With upper girdle facets in place
True Hearts
As you can see, it takes a total of 5 different facets working in harmony to
create a single Heart with an arrowhead at the tip.
1 Heart = 2 main pavilion facets + 2 lower girdle facets + 1 star facet from
the crown
How the Arrows are Formed
In addition to being the foundation of good hearts patterning, the eight main
pavilion facets also cause the Arrow effect. These main pavilion facets are the
bottom-most facets on the diamond and draw their light from the highest angles.
They are the engines which drive light return.
If you have ever wondered what causes these bottom-most facets to appear dark
in diamond photos, click
here for an article on this phenomenon, known as obstruction.
The shaft of an arrow is formed when one main pavilion facet reflects on the
opposite main pavilion facet. The main crown facet allows a different
reflective view of the reflected main pavilion facet, thereby forming the
arrowhead.
Part One Summary: It's All In The Hearts
If the physical symmetry is out in the slightest the optical symmetry will be
affected. In forming the arrows it is easier to camouflage errors since there
are fewer facets to align. But it is impossible to hide any inconsistencies in
the heart pattern because so many more facet reflections must overlap precisely
to complete each heart shape. Even the most minor inconsistencies will make the
hearts pattern skewed or distorted. Any lack of optical symmetry will be seen
very clearly when viewing the diamond through a Hearts & Arrows Viewer,
particularly the pavilion view. This is why "it's all in the hearts."
Final Word
It takes modern tooling, skill and extra time to produce a
diamond with true hearts & arrows. Unfortunately, I see many diamonds sold as
'hearts & arrows' which do not hold to the original standards of the Japanese
factories where such cuts were first produced. The strategy for acquiring a
precise, true pattern must begin with the pavilion patterning. "It's all in the
hearts."
Additionally, hearts & arrows diamonds must be cut for maximum
performance. Those with crown and pavilion angles close to Tolkowsky's have
become known in the trade as 'Superideals.' I strongly feel that any diamond
worthy of being called 'Superideal' must have premium light return and light
performance as fundamental prerequisites, in addition to true hearts & arrows
patterning.
I hope this system is useful to my peers invested in the art of
premium diamond cut. I strongly encourage manufacturers and sellers around the
world to unite and set higher global standards for diamonds we choose to offer
to consumers as 'hearts & arrows' cuts.
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