The Center of Gemological Studies (C.G.S)
was established by Eli Dori in 1979 and offers group & individual gemological courses
according to the students preference.

This is the most prestigious, affluent and respected gemological center in the Israeli Diamond Center
and has taught thousands of students that are working in the diamond industry today.
The C.G.S was chosen by the Israeli Diamond Center to teach the future Members the gemological course.

Eli Dori, is a graduate gemologist (G.G) for the last 40 years, he graduated outstandingly in residence of GIA.
Hadas Dori Bar Moshe graduated gemologist with experience of over 25 years.
They will provide you a comprehensive and intensive gemological course,
in an intimate, pleasant and patient environment, that suites and is adapted to every student.

If you are interested in studying, developing and obtaining experience in the diamond field,
as well as requiring the best professional knowledge and practical grading,
our center is the right place for you!

Gemology Course
Grading And Evaluation
Of Polished Diamonds

The course is taught over a period of 50 hours that include theoretical material as well as practical work which includes the sorting of over 100 polished diamonds by microscope and by loupe. The method by which sorting is taught is according to the GIA and their terminology.

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The Secrets of the Diamond

A captivating and unique lecture about diamonds and the diamonds industry. From Marlyn Monro to "Mazal and Bracha" – Hadas Dori Bar Moshe will take you on a spectacular and entertaining journey to the world of diamonds and it's industry. A lecture that will reveal the hidden secrets and behind the scene stories of this intriguing world.

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About Hadas and Eli

Eli Dori

Eli Dori, B.A in economics and accounting from Tel-Aviv University, Graduated Gemologist (G.G.) outstandingly in residence of GIA in California (diamond and colored stones), writer of the book: "Gemology – The Diamond: Sorting & Evaluation". In 1979 Eli Dori established the: "Center of Gemological Studies" in the Israeli Diamond Center.

Hadas Dori Bar Moshe

Hadas Dori Bar Moshe, MBA from Tel-Aviv University, Graduated Gemologist in the Israeli Diamond Center since 1992, has over 25 years of experience in sorting diamonds and teaching gemological courses.

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The Center of Gemological Studies refers its' students who are looking for work to offices within the diamond industry and to gemological laboratories.

The proportions of the round brilliant cut diamond

The proportions of the round brilliant cut diamond

Diamond proportions Excellent proportions are very important to a diamond because they allow the greatest amount of light to be reflected from the crown. Four key characteristics of a diamond are created by proper proportions: brilliancy, fire, luster and scintillations.   The

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Diamond Substitutes

Diamond Substitutes

Diamond substitutes – the differences between Zirconia and Diamond There are two types of diamond substitutes, natural substitutes and synthetic substitutes. Natural diamond substitutes include: White Spinel White Sapphire White Quartz.   Artificial diamond substitutes include: Synthetic White Spinel Synthetic

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Graining Lines in the diamond

Graining Lines in the diamond

What are graining lines in the diamond? how do they effect the clarity, the quality and the color of the diamond?   Graining Lines in the diamond, are a natural part of the diamond. They affect the clarity and the

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