Grading Hearts and Arrows Diamonds
By Bryan Boyne (g.g.) , Thursday, September 15, 2016
In April 2004 Whiteflash presented our diamond 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 adopt higher standards for diamonds marketed as "Hearts and Arrows". Alhough most laboratories do not offer a grade for Hearts & Arrows, Whiteflash does, thereby safeguarding buyers of the A CUT ABOVE® brand with a guarantee of optical symmetry meeting the IDCC presentation criteria. - Below is from the Whiteflash presentation on Grading Hearts and Arrows Diamonds.
Grading the Hearts
* Note: To understand how facet placement results in hearts and arrows patterning please see our page on Hearts and Arrows Formation.
- Eight equal, uniform and symmetrical hearts
- Eight distinct hearts that separate from the arrowheads above
If above is correct check the following:
- Check to see if the hearts are split
- If so, measure length of heart then the length of the split.
- Calculate the % of the length of the split
If it is greater than 8% and there are more than 2 of them the pattern fails. This can be done visually once a standard of proficiency has been attained.
First, check that there are 8 equal hearts and 8 arrow heads. They must be equal in size and shape as seen in the picture on the left below (True). The picture on the right (Near-True) shows hearts not quite equal in size, but more importantly the hearts split in the cleft. This is not true hearts patterning (not formed correctly - the most difficult case of all is to determine if it is correct or not).
In A1, A2 and A3, the heart is well defined, the gap between the arrow head is distinct and clear, and the split at A3 is minimal versus F1, F2 and especially F3.
Calculating the accuracy of the Hearts, you can measure the length as shown X to Y in 1a, below. Say this is 10mm. If there are any splits in the cleft, this is measured. 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 than 2 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.
Lower Girdle Facets
The length to which lower girdle facets are cut is important to true hearts patterning. Lower girdle halves longer than 80% LGH (or 78.5% LGL) of the length of the mains will cause the cleft in the heart to split and distort the patterning. This is not acceptable.
What Hearts Should Not Look Like
Here are examples of hearts that are not true and are easy to determine.
They are not equal and homogenous and the arrow head and hearts blend together in some cases.
Grading The Arrows
- Each arrow (8) must be clearly visible with a shaft and an arrow head
- The 8 arrow shafts and heads must be straight and in correct position
- The 8 arrow points must meet the girdle
- There must be uniformity and balance
These arrows seem to be acceptable, 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.
Summary: It's All In The Hearts
Precise, true hearts result in precisely formed arrows.
Poorly Formed Hearts result in poor or no arrows.
It takes modern tooling, skill and extra time to produce a diamond with precise hearts and arrows patterning. Unfortunately, we see many diamonds represented in the market as 'hearts and arrows' which do not adhere to the original standards of the Japanese factories where such cuts were first produced. The strategy for crafting a true pattern must begin with precise faceting of the pavilion. That is why we say "It's all in the hearts."
Additionally, hearts and 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.' We strongly feel that any diamond worthy of being called 'Superideal' must have premium light return and light performance as fundamental prerequisites, in addition to precise optical symmetry demonstrated by hearts and arrows patterning.
We hope this system is useful to our peers involved in the art of premium diamond cut. We strongly encourage manufacturers and suppliers around the world to unite and set higher global standards for diamonds represented to consumers as Hearts & Arrows diamonds.
*Learn more in our series on Hearts and Arrows Diamonds:
Hearts and Arrows Grading (this article)
For more specific questions ask our experts