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- Mar 28, 2001
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Greetings PS family,
I wonder if ya’ll could help me out and participate in an exercise I’d like to conduct.
With the usage and popularity of reflector based images and the many sites that are cropping up showing these images I felt it necessary to write an article on the subject to help consumers decipher exactly what it is they are and aren’t seeing with this technology. The title of the article is “A Comprehensive Guide to Reflector Based Technology” which will be covering all the reflector scopes including IdealScope, FireScope, SymmetryScope, LightScope and also the newly released desktop ASET. While I’m not the only person who is familiar with this technology I am perhaps one of the only people who has worked with all of them quite intimately, some more extensively than others. In this article we will be covering
a. History and Development
b. The Future of Reflectors
c. Photography Through the Reflectors
d. The Strengths and Weakness of Reflectors and
e. What Gemological Information Can be Learned from the Reflectors.
Time and hardware/software solutions have prevented me from continuing this article but with the recent arrival of our desktop ASET and Octonus’ Helium scanner we are now equipped to move on. The subject matter of this thread involves the types of information that can be garnered from the optical signature of a diamond as seen and observed through reflectors (this one being LightScope in particular) and is something I’ve been studying over the course of the past 5 years.
The goal of this thread is simply to see if I am communicating this particular subject in a manner that is easy to understand to the layman. While knowledge is a wonderful thing, if it can not be communicated in meaningful terms and language that a common layman can understand then I have failed in my job as an educator and must return to the drawing board. This is why I appreciate any feedback I get in this experiment. As a small reward in participating I will be treating the first 20 people who get the 2 answers correct that I''ll be asking. I''ll featuring a graphic taken through LightScope (taken by myself) of a diamond and will ask 2 questions about it which we’ll get to in a moment. People in the trade may participate as well but only to the first 20 consumers who get the 2 answers right will we send a gift certificate to Starbucks. 
Leonid if you could, I respectfully ask that you keep this thread at the top of the forum so the consumers have a chance to participate and win if they get the answres correct.
The Study: Azimuth Angles and Their Impact Upon the Optical Design of a Round Brilliant Cut Diamond
What are azimuth angles you might ask?
Each facet of a diamond is cut to two different angles/orientations. (See graphic below) One of those angles would be considered the slope angles. The other would be azimuth angles. When a person reads an AGS Report or a Sarin/OGI Report the angles that are being reported are slope angles. In most instances it is just an average of the 8 crown bezels and the 8 pavilion mains. The slope angles are those which are measured in the north/south orientation and many gemologist’s and even expert layman are familiar with what combinations of slope angles produce good brilliance within a diamond.
Non-contact measuring devices such as Sarin and OGI show the appraiser/jeweler the details of these slope angles. Some in greater detail than others depending upon the hardware/software configuration they purchased from that manufacturer as there are differing models of Sarin/OGI machines ranging from 6k to 25k. We are proud to announce that besides AGS and GIA we are the first American gem lab to possess what some experts have described as “the finest measuring device available today”. This measuring device is Helium and I can’t help but agree with those who have seen or used it. I have seen the results from it but only now, with hands on experience am I really beginning to learn and understand the capabilities of this awesome piece of gemological lab equipment.
Ok … so … slope angles are measured in the north/south orientation. Well … facets are also cut in an east/west orientation as well. This east/west orientation would be referred to as the “azimuth angle” and is generally not found in any appraisals you’ll see as no non-contact measuring devices report the results of azimuth angles or how far they deviate from ideal (besides Helium). Up until now this has generally remained amongst the conversations of cutters so I will do my best to communicate this to the layman.
When the azimuth angle of a diamond deviates to a certain degree away from being ideal a shift in the facet occurs resulting in what would properly be described as yaw. To our knowledge and to his credit Brian of WF is the first cutter to use the term and identify this east/west shift in the pavilion view through a Hearts & Arrows viewer through the pavilion side of a diamond. All kudos’ to Brian for making the identification and pointing this out as well as Bruce Harding for graphics demonstrating the phenomena in a simple and easy to understand manner. While the focus of my personal studies has been the effects of this east/west shift through the crown, Brian’s focus has been the observance of it through the pavilion and we would agree that the pavilion view would be the easiest way to assess this feature of azimuth angles resulting in yaw since there are many factors that can alter a diamonds optical signature (such as tilt, out of roundness, etc.). However since a diamond is viewed through the crown the focus of our study concentrates on answering the question “How does a shift in pavilion azimuth angles affect the optical design of a diamond in the face up position?”
You see, before yaw can be considered, there must be an altercation in the azimuth angles first. If we can identify & photograph the shift in azimuth angles then the logical conclusion is that we can also photograph and observe the effects of yaw in the face up position as well but let’s not jump ahead of ourselves. After the teaching I will be posing the following questions to those consumers who would like to participate. After posting a reflector based image with NO numbers I will be asking the following questions.
1. Which facet(s) deviate from ideal?
2. Which orientation (east or west) does the facet shift to?
If after the teaching most people are getting it wrong then back to the drawing board for me.
Let’s begin the study.
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