Is the BrillianceScope the PERFECT machine for looking at cut quality?  If not, what are it's deficiencies?

While I am a strong advocate of the technology it would be unjust if I did not give my opinions on what I would consider are the shortcomings of the technology.

1. With some diamonds it can give an inaccurate reading for scintillation. 

The accuracy can be quickly ascertained by a review of the 5 primary images. Take for example this diamond with 3 Very Highs and look at how much activity there is in the 5 primary light positions.

Now here is a diamond with light return and scintillation that is no less equal than the stone above yet look at the scintillation reading.   This diamond is NOT lacking in scintillation yet if one were fixated on the bar graphs they would be mistakenly led to believe so.

The reason for this is because the BrillianceScope, when ascertaining scintillation is reading the many points of light within the diamond as the light source is moving from position to position.  When diamonds (such as the one above) emanates large splotches of light the BrillianceScope is reading fewer larger points of light instead of many tiny smaller ones thus giving the diamond it's unduly hit in scintillation.  Here is a diamond with similar BrillianceScope results that deserved it's hit in scintillation.  You can see *why* when you look at the 5 primary images. There is a lack of activity in positions 4 & 5 due to other factors in the cutting of the minor facets that affect this.

2. The BrillianceScope does not assess another vital aspect of cut quality which is the component of optical symmetry.

Assessment of cut quality that focuses only on light return and not the components of contrast brilliance/scintillation and optical symmetry is not giving the entire story of cut quality.  While direct light is one of the primary light sources people observe diamonds under there are other light conditions that diamonds are observed under and there are aspects of diamond beauty that are not fully covered in the BrillianceScope analysis. 

Optical symmetry relates directly to craftsmanship, which IMHO should be rewarded when a cutter takes his time to cut a precision cut product.  Take the 2 diamonds below as an example.  One has common optical symmetry while the other was cut to a much greater level of precision.  The photographs tell all.  However both of these diamonds receive a "triple very high" on the BrillianceScope.

	Optical Symmetry	BrillianceScope Results
common optical symmetry		click for full image
ideal optical symmetry		click for full image

3. The BrillianceScope can not accurately ascertain contrast.  Contrast is a major contributing factor to brightness which is primarily the observance of light and dark reflections within the diamond as observed by the human eye in diffuse daylighting.  This example is of a diamond we had here in the past and didn't photograph it under daylighting so this simulated graphic via GemAdvisor will have to suffice.

In Office Lighting	ASET	BrillianceScope Results
		click for full image
Appearance too dark	poor distribution of blues	This tells us the stone does have very good fire but suffers in daylight conditions.

The above stone is evidence how you can have a diamond that appears one way in one lighting environment and entirely different in another.

4. The BrillianceScope can not ascertain painting or digging of the girdle facets.  Painting and digging of the girdle facets contributes to a decrease in brightness, primarily observed in daylight conditions.  To learn more about painting and digging and how it impacts brightness I refer you here.  For your convenience here's an ASET image of a painted diamond along with a dug out girdle and their BrillianceScope results.

	ASET	BrillianceScope
painted girdle		click on image for full size
dug out girdle		click image for full size

5. While it does agree with human eye observation the majority of the time there are circumstances wherein it doesn't.  Please see our case study at this link for more details.