Diamond Characteristics (Advanced) – Tolkowsky

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Most of a brilliant diamond’s sparkle and liveliness comes from its cut. Rough diamonds are often cut to retain carat weight, which results in light leaking out the back of the diamond, and often produces a dull lifeless diamond with a smaller diameter.



In 1919, Marcel Tolkowsky (an engineer by education and member of a Belgian family of diamond cutters) wrote a master’s thesis on the ideal proportions for round diamonds. The ideal proportions designated by Tolkowsky were derived from mathematical calculations that considered both the fire and brilliance of the stone; these diamond proportions have generally been considered as well chosen and have been the industry benchmark for diamonds labeled as “ideal” for the past 80 years.

The target set by Tolkowsky to be considered “ideal” was of a diamond with:

When undertaking a diamond search, finding the best diamonds starts with finding ideal cuts.


It is important to note that Marcel Tolkowsky’s ‘ideal proportions’ were intended as a set of general guidelines as certain aspects of a diamond’s cut had not been taken into consideration or explored. This generalization in Tolkowsky’s concept of ideal diamond proportions has lead to marketing and branding campaigns that often inaccurately label diamonds as “ideal” even though their properties do not fall within the designated tolerances that are considered “ideal”.  Conversely, studies have shown diamonds OUTSIDE of the proportions indicated by Tolkowsky can be equally or even more beautiful than a Tolkowsky Ideal Cut Diamond.



A brilliant diamond is a complex interrelationship of light reflecting and refracting off the many facets of a diamond as light travels through it.  As such, determining which diamonds are desirable and which are overvalued can be tricky.  When starting your diamond search, use Tolkowsky’s ideal proportions as a baseline and a starting tool to help you filter the good from the bad.  Other tools such as Ideal Scope and ASET reports will help you narrow down the best diamond from your set.



The diamond trade is composed of numerous diamond traders and jewelers around the world selling diamonds of varying quality.  For the average consumer, it can be a long and difficult process evaluating diamonds and judging their appearance based on the cut factors listed by the jeweler.  The Holloway Cut Advisor (HCA) is a system which has been developed whereby the various cuts of a diamond are assessed according to factors that characterize the beauty and desirability of the diamond.  In other words, the Holloway Cut Advisor is a tool that helps you find the diamond cut with the most sparkle.

The Holloway Cut Advisor system characterizes diamonds with optimum beauty in three distinct types*.

  • Brilliant Ideal Cut (BIC)
  • Tolkowsky Ideal Cut (TIC)
  • Fiery Ideal Cut (FIC)

* To qualify as an HCA ‘Ideal Cut’ within the HCA system, a diamond must rate as excellent or score less than 2.0.  A score below 2 (Excellent) means you have eliminated known poor performers (more than 95% of all diamonds). Your own personal preference may be for a diamond with an HCA score of 1.5 more rather than one with a lower score of say 0.5.



Brilliant Ideal Cuts (BIC) have the highest return of light and larger spreads (diameter)

Fiery Ideal Cuts (FIC) have more fire and appear to have more facets and scintillation because of the increased interaction between the steeper crown facets

Tolkowsky Ideal Cuts (TIC) combines a balance of fire and brilliance.  Diamonds matching this grading often command a premium due to their overall high performance.



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