Posts by ACA Gemological Laboratory
Round Brilliant Cut Beauty and Light Performance Part 1
Round Brilliant Cut Beauty and Light Performance Part 1 Going back over 100 years, numerous efforts have been made to analytically prove the superiority of the small range of angles called ‘Ideal’. Several metrics and methods have been developed in attempts to provide this proof. Ray tracing was employed by many (e.g. Marcel Tolkowsky…
Read MoreRound Brilliant Cut Beauty and Light Performance Part 2
Round Brilliant Cut Beauty and Light Performance Part 2 Going back over 100 years, numerous efforts have been made to analytically prove the superiority of the small range of angles called ‘Ideal’. Several metrics and methods have been developed in attempts to provide this proof. Ray tracing was employed by many (e.g. Marcel Tolkowsky in…
Read MoreDiamond’s Spectral Constellation
Discover the ‘Diamond’s Spectral Constellation’. Michael D. Cowing explains why the ‘Spectral Constellation’ is the ‘nexus’ connecting a diamond cut’s light performance and its illumination and why it is the key to understanding the occurrence of fire in a diamond when used as a gemstone optical analysis technique. Diamond’s Spectral Constellation
Read MoreHistory and Utility of Gemstone Reflection Pattern Generation and Analysis
A contribution to knowledge in the field of diamond and gem optics, faceting, and design. It is a contribution to the World Gem Foundation’s quarterly journal, ‘Gemmology Today’. The whole journal issue is a free download. Geoff Dominy, World Gem Foundation: I feel very fortunate to know Michael Cowing. He has a brilliant mind.…
Read MoreDescribing Diamond Beauty and Light Performance
The full text of the article is available here.
Read MoreObjective Diamond Clarity Grading
The diamond clarity grading scale used worldwide today was introduced by the Gemological Institute of America (GIA) in 1953. To help address varying interpretations and inconsistencies in clarity grading between laboratories (and even within some labs), this article introduces an objective system for diamond clarity grading. The determination of the clarity grade is influenced by…
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