This page contains references to diamonds or engagement rings from different companies. Sometimes I do receive a commission when you click on links and buy the products.

The principle of the Ideal Scope tool is based on the findings and developments of the Japanese scientist, Okuda, in the 1970’s. Okuda developed ways to assess diamond light performance by using magnified scopes and colored reflectors. His findings contributed to a modern version of this assessment, the Ideal-Scope, championed across the internet by Garry Holloway. The ideal-Scope is a magnifying tube fitted with a red reflector. To view the diamond, the girdle is aligned with the base of the tube. Any light entering from above the crown that is properly returning to the eye will appear red. Any light leakage (light that is escaping and not being returned) from the pavilion of the diamond will appear as white. The obscuration (light from the highest angle that is blocked by the viewer) will appear as black.

Image courtesy of

Understanding and Interpreting Ideal-Scope Images

Interpreting an Ideal-Scope image is fairly simple and it is a key indicator of the diamond’s ability to return light and other aspects of the diamond’s cut quality and symmetry.

Image courtesy of

This reference chart taken from the Ideal-Scope website shows how the Ideal-Scope images can be interpreted and used to make informed decisions when buying a diamond.

  • Areas of black indicate light returned at the highest angles. The Ideal-Scope presents as dark because the light from directly above the diamond is blocked by the camera (obscuration).
  • Red areas indicate the brightest light being returned effectively to the eye.
  • Pink areas indicate a light return that is less intense.
  • White of greyish areas indicate light leakage; light that is escaping from the pavilion of the diamond and not being returned to the eye.

What to Look For

Diamonds of optimum cut quality will be presented through the ideal-scope as an abundance of red, minimal white or grey areas and a symmetrical patterning of black arrows from the centre of the diamond. Average cut diamonds will show areas of pink and grey and also some white light leakage, A poorly cut diamond will show large areas of white indicating light leakage and a chaotic pattern with little to no symmetry.

The Ideal-Scope image can also give an impression of the proportions and symmetry of the diamond. Optical symmetry can be read in the Ideal-Scope images as a sharp pattern of arrows in the crown, while good proportions can be seen through a strong light return (red areas).

Contrast and Light Leakage

Contrast is an essential factor in creating the distinct ‘twinkle’ that a diamond has. This twinkle is known as scintillation, and is created by the necessary dark areas of obstruction which balance with the areas of light. This contrast gives a blinking affect and in the right amount it contributes to the beauty of a diamond.

Image courtesy of Whiteflash

This Ideal-Cut diamond from the in-house A CUT ABOVE® diamonds by Whiteflash, shows positive areas of white that from a uniform pattern around the perimeter of the diamond. This is an example of small amount of unreturned light contributing to the contrast within a diamond, and should be interpreted as a positive when seen in an Ideal-Scope image.

Diamond Reflectors and ASET Technology

Although an older method for assessing light performance in a diamond, reflectors continue to be a simple and reliable tool which can give helpful insight with little need to extensive technical knowledge. The AGSL (American Gem Society Lab) advanced this technology with their creation of the ASET device (Angular Spectrum Evaluation Tool). The ASET can provide a more in-depth analysis about how the diamond is handling light. The ASET framework also works in conjunction with the AGS light performance grading system – a precise, computerised grading system based on the ASET.

Are ASETs Issued as Standard?

As cut quality and light performance play such a crucial role in the beauty of your diamond, the Ideal-Scope is an excellent place to begin when analysing your diamond. The images are easy to interpret and can indicate areas of light leakage that might be missed when viewing the diamond (or a high res image) with an untrained eye however many companies still fair to provide them:

Whiteflash Blue Nile James Allen Brilliant Earth Ritani
HD Video Imaging

(only on request)

Diamond Image

(only on request)

Ideal Scope

Hearts & Arrows

(only on some diamonds)

Sarine Report


When looking for a diamond with exceptional cut quality and light performance I recommend Whiteflash. Not only are their A CUT ABOVE® diamonds are some of the highest performing on the market, but their dedication to presenting technical data pertaining to their diamonds is exemplary, I would also recommend looking at James Allen and their True Hearts Diamonds.

Richard Jenkins, The Diamond Guru

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