In April 2004 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 Whiteflash ACA brand with a guarantee of optical symmetry meeting the IDCC presentation criteria. - Here is Whiteflash's  presentation on Grading Hearts and Arrows

Grading the Hearts

Check for:

1. Eight equal, uniform and symmetrical hearts
2. Eight distinct hearts that separate from the arrowheads above

If above is correct check the following:

1. Check to see if the hearts are split
2. If so, measure length of heart then the length of the split.
3. 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. 

Examples 

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 Accuracy 

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.  Click here for more detailed information on the role of the lower girdle facets in diamond performance.

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

Check for:

1. Each arrow (8) must be clearly visible with a shaft and an arrow head
2. The 8 arrow shafts and heads must be straight and in correct position
3. The 8 arrow points must meet the girdle
4. There must be uniformity and balance

Near-True

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.

Non-True 

Summary:  It's All In The Hearts 

Precise, true hearts result in precisely formed arrows.

Poorly Formed Hearts result in poor or no arrows.

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.