THE RESEARCH LIBRARY
A closer look
at diamond cut.
Twenty-nine chapters from Garry Holloway’s original research, brought together for easier reading. The scientific discussion reflects its original period; current tools and services are linked separately.
Research foundations
7 CHAPTERSAbstract
The ideas behind Garry Holloway’s research into round brilliant diamond cut.
Read chapter 2 MIN READIntroduction
Why cut matters to the appearance and desirability of a round brilliant diamond.
Read chapter 3 MIN READInverse relationship
Exploring the relationships between diamond proportions and light performance.
Read chapter 5 MIN READPrevious research
A review of superior proportion combinations as proposed by other investigators was published in the GIA Brilliance study (Fall 1998). None of these.
Read chapter 2 MIN READDeveloping HCA
The HCA system is designed to satisfy a consumers’ reasonable expectation that cut standards describe the quality and appearance of a diamond. It aims to.
Read chapter 5 MIN READMethod
The method used in the original HCA research.
Read chapter 1 MIN READSummary
Key observations from the original round brilliant cut research.
Read chapterLight performance
6 CHAPTERSBrilliance, fire, scintillation & spread
Brilliance is the human perception of diamond brightness. Brilliance is not simply light return, it involves complex issues that include scintillation or.
Read chapter 1 MIN READBrilliance
Understanding the brightness that gives a diamond its visual presence.
Read chapter 2 MIN READFire or dispersion
Exploring the coloured flashes produced as a diamond disperses light.
Read chapter 2 MIN READScintillation
The flashes and pattern of light and dark that change as a diamond moves.
Read chapter 2 MIN READSpread
How proportions influence the apparent size of a diamond when viewed from above.
Read chapter 4 MIN READSeeing is believing?
This optical illusion shows how our perception can corrupt a signal received by the eye. Lateral inhibition results from the ability of one part of the.
Read chapterProportions & grading
10 CHAPTERSTable size
Table 3. Adjustments made for table size. Arrows (<- />) indicate penalties continue below 50% and above 65% table sizes. Table size: Too Small Optimum.
Read chapter 3 MIN READGirdle thickness
The GIA Brilliance study found the impact of girdle thickness on diamond beauty was minimal. I concur. Ray path analysis shows that polished girdles.
Read chapter 2 MIN READFisheye
A ‘fisheye’ appears as a circular inclusion just inside the table, and in extreme examples can look like an I3 inclusion. The fisheye effect is a.
Read chapter 2 MIN READCulet
A large culet on a diamond allows a surprisingly small amount of light loss because most ray paths from light entering the crown of a diamond travel at.
Read chapter 2 MIN READAdjustment to HCA
The HCA is designed to aid a novice consumer or an experienced trade buyer in selecting unseen diamonds as though each diamond were lined up side-by-side..
Read chapter 5 MIN READNo-go zone
We are now going to look in more detail at a zone of poorly performing crown and pavilion proportion combinations, or ‘no go zone’ (NGZ). There has been.
Read chapter 4 MIN READFlawed cut grading
Demand for diamonds with top cut grades endorsed by internationally respected institutions has increased dramatically in the past decade since Sarin.
Read chapter 2 MIN READBIC and FIC
The cut adviser system recognizes three distinct types of diamonds with optimum beauty. To qualify as an HCA ‘Ideal Cut’ a diamond must rate as excellent.
Read chapter 2 MIN READMarket values
In 1979 Martin Rapaport began a service reporting diamond prices based on carat weight, color and clarity. Today most business-to-business diamond trading.
Read chapter 2 MIN READAccuracy
The accuracy of digital proportion measurements is far superior to what was achieved with optical devices a decade or two before. Sarin Technologies and.
Read chapterTools & references
6 CHAPTERSHolloway Cut Adviser
How HCA uses diamond proportions to help narrow the search for round brilliant diamonds.
Read chapter 1 MIN READDiamCalc
DiamCalc is software that models virtual polished diamonds and ray paths as well as create "movies" of a stone being rocked from side to side, a limited.
Read chapter 1 MIN READDiamCalc information
If you have already downloaded the DiamCalc trial version skip to 6. If you have haven't, start from 1. 1. First - print this page so you can refer back.
Read chapter 2 MIN READFire- & Ideal-Scopes
How reflected light helps reveal brightness, contrast and leakage.
Read chapter 1 MIN READGilbertsonScope
Mr. Al Gilbertson displayed a multi colored variation of a Fire Scope™ at the proceedings of the 1999 GIA Symposium. This device uses different colors to.
Read chapter 1 MIN READLinks & references
Jasper Paulsen has done a fantastic job of putting the whole of Tolkowsky's 1919 book "Diamond Design" onto the Internet for all to read. But not content.
Read chapter