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HCA - Defining the Beauty and Desirability of Round Brilliant Diamonds

The Fire Scope™ and Ideal-Scope

Invented in Japan, the Fire Scope™ has a white light source that floods the pavilions of stones that sit in holes in a Perspex tray. Above the diamond is a disk of bright reddish pink paper which is also illuminated from the light below. Diamonds are viewed through a 10X lens via a hole in the pink disc. By visually estimating the amount of red light refracted and reflected back from the diamond an observer can gauge light return.
 
In 1984 after acquiring a Fire Scope™ I used it commercially for selection and sale of diamonds. I later made hand held portable devices that had a larger area of pink encompassing all light illuminating the crown. This new instrument is sold and marketed as the Ideal-Scope and demonstrations can be viewed at www.ideal-scope.com.
 
The intensity of red, together with the amount of white (light leaking from behind the stone), indicates a diamonds face up light return. Blackness indicates the darkened area of light that originates from, and returns to the lens. This approximates the darkness cast by an observer with head that blocks a 31° or illumination for the Fire Scope™ and a more realistic 24° for the Ideal-Scope.
 
Experienced users can interpret the black patterns of darkness that originate from the lens and assess the symmetry and scintillation of a diamond. Diamonds that exhibit a symmetrical star shaped black pattern are by definition ‘optically symmetrical’ and if that blackness is evenly dispersed and covers approximately 10 - 20% of the stone then the diamond will display pleasing scintillation.
 
In my experience any diamond that displays an exceptional Ideal-Scope image is ‘ideal cut’ by definition, what ever its proportions.
 
The name ‘fire-scope’ is poorly chosen since the device is of little assistance in assessing fire.
 

 
The best cut diamonds look bright red or pink through an Ideal-Scope or Firescope™. This is due to the reflection from the pink positioned to supply optimal illumination surrounding the lens. White is bad as it indicates light leakage out the pavilion. Darkness originates from the lens area (blackened by the observers eye), a moderate amount is desirable. A strong black star / arrows pattern indicates good symmetry. The stars are effectively the same as seen in Hearts and Arrows diamonds. H&A’s viewers were a by product of the original Firescope™.
 

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